Class 10

Punjab State Board PSEB 10th Class Agriculture Book Solutions Chapter 6 Agroforestry Textbook Exercise Questions and Answers.

PSEB Solutions for Class 10 Agriculture Chapter 6 Agroforestry

Agriculture Guide for Class 10 PSEB Agroforestry Textbook Questions and Answers

(A) Answer in one-two words:

Question 1.
How much area should under forests in Punjab, as per National Forest Policy 1988?
Answer:
20%.

Question 2.
How much area is under forests and tree cover in Punjab?
Answer:
6.49%.

Question 3.
How many major agro climatic zones are there in Punjab on the basis of climate?
Answer:
Three.

Question 4.
In which season acute shortage of fodder is felt in Kandi region of Punjab?
Answer:
In winter.

Question 5.
What is the spacing for planting of poplar on boundary of a field?
Answer:
3 metres.

Question 6.
What types of .soils are there in Kandi region?
Answer:
Soil is undulating that is not uniformly levelled. It has many ups and down.

Question 7.
Name two trees used for fodder in Kandi region.
Answer:
Dhak, Beri, Chhal, Kachnar etc.

Question 8.
What should be the pH of soil for poplar cultivation?
Answer:
6.5 to 8.0.

Question 9.
Name the trees suitable for commercial agroforestry in Punjab.
Answer:
Poplar, Eucalyptus

Question 10.
How many Poplar plants are planted in per hectare?
Answer:
200 trees per acre.

(B) Answer in one-two sentences:

Question 1.
What is the planting time of Poplar in Punjab?
Answer:
Suitable time for planting poplar in Punjab is January-February.

Question 2.
Define Agroforestry.
Answer:
Agroforestry is a land management system in which cultivation of trees and crops is done together in a field along with rearing of animals on the same piece of land.

Question 3.
What type of soil and irrigation facilities are available in Central plain zone in Punjab?
Answer:
In this zone, soil is fertile and irrigation facilities are available here.

Question 4.
What type of trees are found in S-W region of Punjab?
Answer:
Kikar, Tahli, Mango, Dhrek, Nim, Jamun, Toot etc. trees are planted in south-western zone.

Question 5.
Write down planting and spacing requirements of Eucalyptus.
Answer:
Cuttings are used for the propagation of Eucalyptus. Eucalyptus can be planted on the boundaries of the field or in block plantation. Plant to plant spacing on the boundaries should be 2 metres and if planted in block plantation the spacing should be 4 x 2 m.

Question 6.
Write the clones of poplar planted in Punjab.
Answer:
PL-1, PL-2, PL-3, PL-4, PL-5, L-47/88, L-48/89 are clones of poplar.

Question 7.
What is the planting time of Eucalyptus in Punjab?
Answer:
Eucalyptus can be planted in March-April and July-August.

Question 8.
Write down the names of the industries where poplar wood is used.
Answer:
Wood obtained from poplar can be used in Match box industry, ply manufacturing, packing cases etc.

Question 9.
What is the spacing for poplar planting?
Answer:
If poplar is planted on boundaries then plant spacing should be 3 metre and if it is planted in die whole field then spacing should be 8 x 2.5 m or 5 x4m.

Question 10.
Write the name of trees grown in Kandi region.
Answer:
Toot, Nim, Tahli, khair, Kikkar, Bel, Kachnar, Mango, Subabaul, Aijun, Harar, Behra, Phalis and dhak, Dehrek, Sohanjana etc.

(C) Answer in Jive-six sentences:

Question 1.
Write down the clones planted and spacing for poplar planting in Punjab. .
Answer:
PL-1, PL-2, PL-3, PL-4, PL-5, L-47/88, L^18/89 are some of the clones of poplar. If poplar is planted on boundaries then plant spacing should be 3 metre and if it in planted is the whole field then spacing should be 8 x 2.5 m or 5 x 4 m. 200 plants per acre can be planted in the field.

Question 2.
Write down the source of clonal Eucalyptus plants in Punjab.
Answer:
We should plant Eucalyptus plants prepared from cuttings in Agroforestry. These all grow uniformely. These can be obtained from any nursery of department of forests and wildlife preservation, Punjab, PAU, Ludhiana or any other private registered nursery.

Question 3.
How poplar can be planted?
Answer:
Make a pit which is 3 feet deep and have diameter of 15-20 cm. Use chloropyriphos and Emisan-6 against termies and diseases. Plant poplar trees in the month of January and February. Water the plants immediately after planting the poplar tree. If poplar is planted on boundaries then plants spacing should be 3 metre and if it in planted in the whole field then spacing should be 8 x 2.5 m or 5 x 4 m. 200 plants per acre can be planted in the fields.

Question 4.
Where poplar wood is used?
Answer:
Cultivation of poplar is helpful in creating employment and also in small enterprises in which wood is the raw-material. Poplar is used in various industries e.g. it is used in the manufacturing of match sticks. It is also used in the manufacture of plywood and also in the packaging industry to make boxes. This way one can earn by the cultivation of poplar. It sheds off its leaves in winter thus has no harm for Rabi crops.

Question 5.
Why Poplar and Eucalyptus are suitable for commercial Agroforestry? Or Why are Eucalyptus and poplar cultivated as commercial agro forestry in Punjab?
Answer:
Poplar and Eudalyptus are suitable for commercial agroforestry in Punjab. Wood obtained from these trees can be easily marketed. The income from these trees in more than wheat-rice cropping system.

Safeda:
It grows in less time, stem is straight, its branches shed off regularly. Its wood is used as building material, its pulp is used in paper industry, wooden beams are also obtained from it. Therefore it is suitable for cultivation in agroforestry.

Poplar:
It provides employement. Its wood is used in small scale industry; like, ply, match sticks, packing boxes etc. It also does not affect the Rabi crops.

PSEB 10th Class Agriculture Guide Agroforestry Important Questions and Answers

Multiple Choice Questions

Question 1.
According to National Forest Policy 1988, forests should occupy of area in plain states.
(a) 5%
(b) 20%
(c) 50%
(d) 29%.
Answer:
(b) 20%

Question 2.
In central plain region trees are grown.
(a) Poplar
(b) Dek
(c) Eucalyptus
(d) All
Answer:
(d) All

Question 3.
………….. is not a variety of poplar:
(a) PL-5
(b) PL-47/88
(c) PL-858
(d) PL-48/89.
Answer:
(b) PL-47/88

Question 4.
Poplar trees become ready in years for harvesting.
(a) 5 to 7
(b) 1 to 2
(c) 10 to 12
(d) 15 to 25.
Answer:
(a) 5 to 7

Question 5.
pH value for soil for poplar cultivation.
(a) 10
(b) 6.5 to 8.0
(c) 3 to 4
(d) 4 to 5.5.
Answer:
(b) 6.5 to 8.0

Question 6.
In which direction the trees are planted on ridges of the farms for agro forestry?
(a) North-South
(b) East-west
(c) South-east
(d) North-east.
Answer:
(a) North-South

Question 7.
For timber production after how many years Eucalyptus can be harvested?
(a) 13 to 15 years
(b) 6 to 8 years
(c) 4 to 6 years
(d) 2 to 4 years.
Answer:
(a) 13 to 15 years

Question 8.
For batten production, after how many years Eucalyptus can be harvested?
(a) 13 to 15 years
(b) 6 to 8 years
(c) 4 to 6 years
(d) 2 to 4 years.
Answer:
(c) 4 to 6 years

Question 9.
For paper pulp production, after how many years Eucalyptus can be harvested?
(a) 13 to 15 years
(b) 6 to 8 years
(c) 4 to 6 years
(d) 2 to 4 years.
Answer:
(b) 6 to 8 years

True False:

1. Poplar is more successful in Bet area.
Answer:
True

2. Poplar tree become ready for harvesting after 5-7 years.
Answer:
True

3. To save orchards from wild life, Jatropha are grown around the orchards.
Answer:
True

4. Poplar cultivation is successful in Kallar and water logged soils.
Answer:
False

5. Eucalyptus clonal plants should be planted in Agroforestry.
Answer:
False

Fill in the blanks:

1. Poplar wood is used in the manufacture of ……………. .
Answer:
Match sticks

2. For boundaries poplar trees are planted at spacing.
Answer:
3 m

3. …………….. erosion is major problem in sub-mountainous zone.
Answer:
Soil

4. Pl-3 is a …………….. clone.
Answer:
poplar

5. In winter the scarcity of ……………. is felt in submountaneous zone.
Answer:
fodder.

Very Short Answer Type Questions

Question 1.
Why is agroforestry suitable for Punjab?
Answer:
It helps in increasing the area under the forests and trees.

Question 2.
Can we take income from agroforestry?
Answer:
Yes, more than the conventional agricultural practices i.e. more than paddy-wheat cropping system.

Question 3.
In which direction, trees should be planted on the boundaries of fields? (PS.E.B. 2017)
Answer:
In North-South direction.

Question 4.
In how many zones is Punjab divided on the basis of climate?
Answer:
Three zones.

Question 5.
On what basis the farmer in Kandi area grow their crops?
Answer:
Agriculture is based on the rainfall.

Question 6.
Which of the trees are planted to save the orchards?
Answer:
Jatroffa, Karonda, Ipomea.

Question 7.
What type of soil is found in south-western zone?
Answer:
Saline and alkaline soil.

Question 8.
Poplar is not harmful for rabi crops, how?
Answer:
Its leaves shed off in winter and it is not harmful for rabi crops.

Question 9.
What type of soil is not suitable for poplar?
Answer:
Kallar and water-logged.

Question 10.
In which area poplar is must successful?
Answer:
In bet area.

Question 11.
How many poplar trees can be planted in the field?
Answer:
200 trees per acre.

Question 12.
In how many years poplar trees are ready?
Answer:
5 to 7 years.

Question 13.
What type of Eucalyptus plants should be planted?
Answer:
Prepared from cuttings.

Question 14.
How many Eucalyptus plants are planted In the whole field?
Answer:
500 trees per acre.

Question 15.
If Eucalyptus cultivation is for long time, what should be row spacing?
Answer:
8 metre.

Question 16.
After how many years can we get wood for buildings (timber) from Eucalyptus?
Answer:
13 to 15 years.

Question 17.
After how many years is Eucalyptus ready for pulp?
Answer:
6 to 8 years.

Question 18.
After how many years Eucalyptus is ready for battens?
Answer:
4 to 6 years.

Question 19.
Write file name of two trees which are mainly grown in Punjab for commercial agroforestry.
Answer:
Poplar, Eucatyplus.

Short Answer Type Questions

Question 1.
Write the name bf two main models for agroforestry?
Answer:
There are two main models for agroforestry-Boundary plantation and intercropping in block plantation.

Question 2.
Where do farmers plant trees if they use boundary plantation model?
Answer:
They plant trees on the boundaries of fields.

Question 3.
Which of the trees are used for planting on the boundaries?
Answer:
Subabaul, Drek, Toot, Eucalyptus, Poplar, Siris, Lassora, Sohanjana, Nim, Tahli etc. –

Question 4.
Which farmers do the mixed farming of crops and trees?
Answer:
Those farmers who have more agricultural land can do mixed farming.

Question 5.
Which of the trees are suitable for planting in the whole field?
Answer:
Poplar, Eucalyptus, Dhrek and Tun are suitable trees.

Question 6.
In which area is the problem of soil erosion found?
Answer:
Soil found in the Kandi area is not uniform and land has many ups and downs (undulating) therefore problem of soil erosion is also found there.

Question 7.
Which type of soil is suitable for poplar?
Answer:
Well drained, loamy to sandy, fertile soil and which have pH value from 6.5 to 8.0 is suitable for growing popular.

Question 8.
List four uses of wood of Eucalyptus.
Answer:
Batten, pulp, wood used in buildings construction, industry, furniture

Question 9.
Write the name of four trees which are grown in whole field in agroforestry.
Answer:
Poplar, Eucalyptus, Toon, Dhrek.

Question 10.
Why salinity is found in the upper surface of the soil in the South-Western zone?
Answer:
Water under the earth in this zone is saline. This makes upper surface of the soil also saline.

Long Answer Type Questions

Question 1.
Write about trimming and pruning of poplar? Or Write the benefit of correctly pruning poplar plants at the right time.
Answer:
There is no need of trimming in the first year, but in the second year after shedding off the leaves there is a need of pruning of the trees to make it straight and to give it good appearance. If trimming and pruning is done at proper time then the stem remains straight and without nodes.

Question 2.
Which of the qualities of Eucalyptus make it suitable for cultivation in agroforestry? Or For which qualities Eucalyptus is grown in agroforestry?
Answer:
It grows in less time, stem is straight, its branches shed off regularly. Its wood is used as building material, its pulp i§, used in paper industry, wooden beams are also obtained from it. Therefore it is suitable for cultivation in agroforestry.

Question 3.
Define Agroforestry.
Answer:
According to National Forest Policy 1988, to fulfil the needs based on wood and to keep the environment safe, area under the forests should be 20%. But it is not possible to increase the area under the forests therefore this is achieved by agroforestry. Agroforestry is the cultivation of trees and crops together in the same field. The objective behind this, type of cultivation is that farmers can fulfil their needs e.g. cereals, wood, fuel, fodder and also can save the natural resources e.g. soil, water, air etc. There is also an increase in their income.

Question 4.
What do you mean by agroforestry? Explain in detail about the planting trees on farm boundaries in agroforestry.
Answer:
Do it yourself.

Punjab State Board PSEB 10th Class Science Important Questions Chapter 2 Acids, Bases and Salts Important Questions and Answers.

PSEB 10th Class Science Important Questions Chapter 2 Acids, Bases and Salts

Long Answer Type Questions

Question 1.
What do you mean by neutralization reaction? Explain with an experiment.
Answer:
It is a chemical reaction in which acids reacts with base to form salt and water. It is known as neutralization reaction.

Process of neutralization

Experiment: Take a solution of dilute sodium hydroxide in a beaker. Add few drops of phenolphthalein in this solution. Its colour changes to pink. Take a burette filled with dilute hydrochloric acid. Fix it vertically on a stand as shown in Fig. Place a beaker under it. Add the hydrochloric acid slowly to the beaker with the help of burette and go on swirling the beaker slowly. When the colour of solution disappears then stop adding acid to beaker. Now there is no effect of Red to Blue litmus to the solution. Now there is only salt and water in the beaker which is neutral to litmus. This is known as neutralization reaction.

Example:
HCl + NaOH → NaCl + H₂O
Cu(OH)₂ + H₂SO₄ → CuSO₄ + H₂O
HCl + KOH → KCl + H₂O

Question 2.
Write briefly chemical properties of acids.
Answer:
Acids have several chemical properties :
1. Reaction with metals. Acids reacts with active metals. Zinc, Magnesium, Iron, Mangenese etc. reacts with them to produce hydrogen gas.
Zn(s) + dil. H₂SO₄(aq) → ZnSO₄(aq) + H₂(g)
Mg(s) +dil.2HCl(aq) → MgCl2(aq) + H₂(g)
Fe(s) + dil. H₂SO₄ (aq) → FeSO4(aq) + H₂(g)
Mn(s) + dil. HNO₃ (aq) → Mn(NO₃)(aq) + H₂ (g)

2. Reaction with metals carbonate and metal bicarbonate. Acids reacts with metal carbonate and metal bicarbonate to produce C02.
Na₂CO₃ + H₂SO₄ → Na₂SO4 + H₂O + CO₂
NaHCO₃ + HCl → NaCl + H₂O + CO₂
CaCO₃ + 2HCl → CaCl₂ + H₂O + CO₂
K₂CO₃ + 2HCl → 2KCl + H₂O + CO₂

3. Reaction with bases. Acids reacts with base to show neutralization. They produce salt.
HCl + NaOH → NaCl + H₂O
HCl + KOH → KCl + H₂O
Cu(OH)₂ + H₂SO₄ → CuSO₄ + H₂O

4. Reaction with sulphites and bisulphites. Acids react with metal sulphite and bisulphite to produce SO₂ gas.
CaSO₃ + H₂SO₄ → CaSO₄ + H₂O +SO₂ (g)
NaHSO₃ + HCl → NaCl + H₂O + SO₂(g)

5. Reaction with metal sulphides and hydrogen sulphides. Acids react with metal various metal sulphide and hydrogen sulphides to produce H₂S gas.
FeS + H₂SO₄ → FeSO₄ + H₂ S(g)

6. Reaction with metal Chlorides. When metal chloride heated with acids the reaction takes place.
NaCl + H₂SO₄ → NaHSO₄ + HCl (g)
NaCl + NaHSO₄ → Na₂SO₄ + HCl (g)

7. Reaction with metal nitrates. Concentration acid reacts with metal nitrate.
NaNO₃ +H₂SO₄ → NaHSO₄ + HNO₃
NaNO₃ + NaHSO₄ → Na₂SO₄ + HNO₃

8. Reaction with metal oxides. Metal oxides reacts with dilute acids to form salts of
Na₂O + 2HNO₃ → 2NaHO₃ + H₂O
CuO + 2HCl → CuCl₂ + H₂O

Question 3.
Write in brief chemical properties of bases/alkalis.
Answer:
Important chemical properties of bases/alkalis are given below :
1. Reaction with metals, Bases react with some metals to produce hydrogen gas.

2. Reaction with air. Some bases react with CO₂ present in air.
2NaOH + CO₂ → Na₂CO₃
2KOH + CO₂ → K₂CO₃

3. Reaction with acids. Bases react with acids to produce salts.
NaOH+ HCl → NaCl + H₂O
Fe(OH)₂ + 2HCl → FeCl₂ + 2H₂O
Ca(OH)₂ + 2HCl → CaCl₂ + 2H₂O

4. Reaction with salts. Salts of copper, iron, Zinc etc. react with bases and produce insoluble metal hydroxides.
ZnSO₄ + 2NaOH → Na₂SO₄ + Zn(OH)₂ ↓
CuSO₄ + 2NH₄OH → (NH₄)₂SO₄ + Cu(OH)₂ ↓
FeCl₃ + 3NaOH → 3NaCl + Fe(OH)₃ ↓

Question 4.
What is the importance of pH in everyday life?
Answer:
pH has very important role in our life :
1. In animal world. Many of the processes in our body occur within the pH range of 7-0 to 7-8. We can survive only in this narrow range. pH value of our blood, tears, saliva is nearly 7-4. Survival will become impossible if this value becomes less than 7-0 or more than 7-8. When pH of rain water decreases from 7-0 to 5-6 or less then it is called acid rain. WThen acid rain flows to the rivers then pH value of river water lowers. Survival of aquatic life in such rivers become difficult.

2. For plants. For healthy growth of plants a specific pH range of soil is required. If soil becomes more basic or acidic, produce badly affected.

3. Digestive system. Our stomach produces HCl, which without harming us help in the digestion of food. Duiing indigestion the stomach produces too much of acid. This causes pain and irritation in the stomach. To get rid of this pain, bases are used which are called antacids. For this weak base like milk of magnesia is used.

4. Tooth decay. If pH value of the mouth is lower than 5-5, then tooth decay begins. Our teeth are made up of calcium phosphate which is hardest substance in our body. It is not soluble in water but starts decaying when pH of the mouth is lower than 5-5. Bacteria present in the mouth produce acids by .degradation of sugar and food particles. To get rid of this we should use basic tooth paste. This will neutralize the acid and tooth decay can be prevented.

5. Relief from insect stings. When some insects sting us, they leave a special type of acid in our body. Bees, ants etc. leave methanoic acid in our body by their sting. To get relief from pain, mild base like baking soda is rubbed on the stung area.

6. Safety from special plants. Plants like nettle have stingging hair. By touching them we feel pain similar to insect sting. This pain is due to methanoic acid. Conventionally, one can get relief by rubbing leaves of dock plant on the stung area.

Short Answer Type Questions

Question 1.
What are indicators? How do indicators are categorized? Explain.
Answer:
Those substances which change their colour in acidic and basic solutions, are called indicators.
Indicators are categorized into two types on the basis of their special properties and characteristics.

1. Indicators which give colour to acids and basic medium.
2. Indicators which give smell to acids and basic medium.

1. Colour giving indicators :
(A) Litmus solution: Litmus solution is purple dye which is obtained from Lichen plant. This is available as red or blue solution and also in the form of litmus paper. Blue litmus turn to red in the presence of acids and Red litmus turns to blue in the presence of basic media. Litmus is neither acidic nor basic by itself.

(B) Turmeric: Turmeric change to red-brown colour in the presence of bases. That is why vegetable stain on the clothes becomes red brown when washed by applying soap which is alkaline.

(C) Phenolphthalein: This is synthetic indicator. It gives pink colour in the presence of bases.

(D) Methyl orange: This is also synthetic indicator. It gives pink colour in the presence of acidic medium and yellow in the presence of bases.

2. Olfactory indicators: Chopped onion, vanilla essence and clove oil change smell in the presence of acids and bases act as olfactory indicators.

Question 2.
What is dilution?
Answer:
When we mix an acid or base with water, the number of H+/OH~ ions per unit volume decreases, it is called dilution. By dilution, acids and bases are ionized.

Question 3.
Give characteristics of acids.
Answer:

• They are sour to taste.
• They turn blue litmus to red.
• Their solution is not like soap solution.
• They produce hydrogen gas when reacts with metals.
• They react with carbonates to produce carbon dioxide.
• Acid react with bases to produce salts and water.

Question 4.
Give four uses of acids in our everyday life.
Answer:

1. Vinegar is used in cooking food and acts as preservative and used in pickles.
2. HCl in our stomach destroys the harmful bacteria, which reach there with our food.
3. Tartaric acid is used to prepare baking soda.
4. Carbonic acid is used in soft drinks.

Question 5.
What are the harmful effects of acids in everyday life?
Answer:

• They can destroy living cells.
• Concentrated acids can badly damage the skin and soft organs.
• These can damage eatables.

Question 6.
Differentiate between strong acids and weak acids.
Answer:

Question 7.
Differentiate between strong base and weak base.
Answer:

Question 8.
Categorize the following compounds as strong and weak acids and bases,
(i) HCl
(ii) H₂SO₄
(iii) CH₃CHOOH
(iv) HCN
(v) NH₄OH
(vi) H₃PO₄
(vii) NaOH
(viii) Ca(OH)₂
(ix) KOH
(x) H₂CO₃
Answer:

Question 9.
What is the reason for electric conduction in acids? Explain.
Answer:
Acids produce H+ ions. Due to ions acids can conduct electricity. This conduction takes place in water solution.
HCl + H₂O → H₃O + +Cl^–
HNO₃ +H₂O → H₃O+ +NO₃^–

Question 10.
What happens when a base is dissolved in water? Explain it.
Answer:
Bases when dissolved in water give hydroxide OH^– ion. The water-soluble bases are called alkalis.

Question 11.
Why are bases not touched or tasted?
Answer:
Bases have a bitter taste like soaps and are harmful to skin. They are harmful when touched or tasted.

Question 12.
Write uses of alkalies/bases.
Answer:

• These are used to make soap.
• These are used in basic batteries.
• These are used in making antacids.
• Used in Petrol refining and paper industry.
• To remove stains of grease from cloths.
• To make hard water, soft.

Question 13.
Give normal characteristics of bases.
Answer:

• They are bitter to taste.
• They are soapy to touch and are harmful for skin.
• These turn litmus to blue.
• These turn turmeric to red brown colour.
• These react with acids to produce salts and water.
• They turn phenolphthalein solution to pink.

Question 14.
What is difference between alkali and base?
Answer:
Those alkalies which are soluble in water are called bases. This means all bases are alkalies but all alkalies are not bases, e.g. Ferric hydroxide [Fe(OH)3] and cupric hydroxide [Cu(OH)2] are alkalies but are not bases since these are not soluble in water.

Question 15.
What are the sources to get common salt (NaCl)? Explain.
Answer:
We can get common salt from following sources :

• Sea water: A huge amount of salt is dissolved in sea water. Salt in obtained from sea water through salt shallows. Solar heat and air help in the evaporation of sea water. We get salt.
• Mineral salt: Deposits of solid salt are found in many parts of the world. These beds of rock salts were formed when seas of bygone ages dried up. This salt is mined similar to the mining of coal. These rocks are found in Mandi (Himachal Pradesh), Khewra (Pakistan). Due to impurities this salt is brown in colour.
• From Lakes: Salt is obtained from Sambher lake in Rajasthan, great salt lake in America, Lake Elton in Roose etc. This salt in obtained by evaporation.

Question 16.
Write characteristics of common salt.
Answer:

• Colour and state: It is colourless crystalline substance which melts at 820°C.
• Solubility: Salt is soluble in water.
• Effect of heat: On heating salt a cracking sound is produced due to breaking of ‘ salt crystals.
• Hygroscopic: Salt absorb moisture from the air, This is due to presence of magnesium and calcium chloride.

Reaction with sulphuric acid. Salt reacts with concentrated sulphuric acid to produce HCl gas.

Reaction with silver nitrate. Salt reacts with silver nitrate to form white precipitates of silver chloride.
AgNO₃ + NaCl → AgCl + NaNO₃

Question 17.
Give uses of common salt.
Answer:

• Salt is important constituent of our food.
• This is used as preservative in many eatables.
• It is used in soap, pottery industry.
• It is used in making freezing mixture.
• It is used in the preparation of bleaching powder, caustic soda, hydrochloric acid, washing soda, Baking powder etc.

Question 18.
What is chlor-alkali process? Give pictorial representation of the products of this reaction. Give their uses.
Answer:

Important products of chior-alkali process.

When current is passed through aqueous solution of salt gets dissociated and sodium hydroxide is produced. This is known as chlor-alkali process because the products in this reaction are chlorine (chlore) and sodium hydroxide (base)
2NaCl(aq)+ 2H₂O(l) → 2NaOH(aq) + Cl₂(g) + H₂(g)

All these products are very important and useful in industry medicine, home and cosmetics etc. Chlorine and hydrogen are the by products of this process.

Question 19.
How is bleaching powder prepared? Give its common characteristics and uses.
Answer:
Bleaching powder is obtained by the reaction of chlorine with slaked lime.

To manufacture bleaching powder at large scale, we have a special tower there is a hopper at the top of tower, slaked lime is added through this hopper. At the bottom hot air and chlorine gas are blown. Chlorine moves upwards and is absorbed completely by slaked lime and bleaching powder is produced.

Characteristics :

• Bleaching powder is light yellow coloured powder, It has a sharp smell of chlorine.
• It is soluble in water, but not completely.
• It reacts with CO₂ of air and loose its chlorine.
  CaOCl₂ + CO₂ → CaCO₃ + Cl₂
• It reacts with acids
  CaOCl₂ + 2HCl → CaCl₂ + H₂O + Cl₂
  CaOCl₂ +H₂SO₄ → CaSO₄ + H₂O + Cl₂

Uses

• It is used in paper and textile industry.
• Used to disinfect drinking water to make it free from germs.
• It is used to make unshrinkable work.
• It is used for preparing chloroform.
• It acts as oxidising agent.

Question 20.
Write chemical formula for washing soda. When its crystals are open in air, then what happens?
Answer:
Chemical formula for washing soda is Na₂CO₃. 10H₂O. When its crystals are left open in air then due to efforescence nine molecules of water are lost in the air.
Na₂CO₃.10H₂O → Na₂CO₃ .H₂O + 9H₂O

Question 21.
What happens when solution of sodium hydrogen carbonate is heated? Give chemical reaction for the equation.
Answer:
When sodium hydrogen carbonate solution is heated then carbon dioxide gas is produced and sodium carbonate is produced.

Question 22.
What is common name of the compound CaOCl₂? Name the substance which reacts with chlorine to produce bleaching powder?
Answer:
Common name of compounds CaOCl₂ is bleaching powder. The substance which reacts with chlorine to produce bleaching powder is slaked lime [Ca(OH)₂],

Question 23.
If during the preparation of plaster of Paris the process of heating is not controlled then which substance is formed?
Answer:
Temperature should be maintained at 373 K during the preparation of plaster of Paris. If temperature is not controlled then unhydrated calcium sulphate (CaSO₄) is produced which do not have the properties of plaster of Paris. This is known as dead burnt Plaster.

Question 24.
Explain preparation, properties and uses of baking soda (NaHCO₃).
Answer:
Chemical formula for baking soda is NaHCO₃ and its chemical name is sodium bicarbonate. It is formed when CO₂ is passed through aqueous solution of Na2CO₃.
Na₂CO₃ + CO₂ + H₂O → 2NaHCO₃

It can also be prepared from sodium chloride.

Properties: When it is heated it swells and becomes light. On heating it produces CO₂. It is soluble in water.

Uses :

• It is used in the preparation of baking powder.
• It acts as antacid in case of acidity in the stomach.
• It is also used in soda-acid fire extinguishers.

Question 25.
Explain the following processes.
(i) Deliquescence
Answer:
Deliquescence: When some compounds absorb moisture from air and change to solution then this process is called deliquescence.
e.g. common salt is deliquescence.

(ii) Bleach.
Answer:
Bleach: When some gas or compound decolourises something, this is known as bleach, e.g. bleaching powder or chlorine is used for this purpose.

Question 26.
What happens when carbon dioxide is passed through fresh lime water?
Answer:
When carbon dioxide is passsed through fresh lime water in small quantity then insoluble calcium carbonate is formed and colour of lime water turns to milky.

If excess of CO₂ is passed through this solution, calcium carbonate change to soluble bicarbonate and milkiness disappears.

If this solution is heated again, milky colour again appears because calcium bicarbonate again change to calcium carbonate.

Question 27.
What is pH scale? How does it respresent acidic and basic nature of a solution? Represent whole range of pH and [H₃O]⁺.
Answer:
A scale which is used to know the concentration of hydrogen ion in a solution is called pH scale. Here ‘p’ stands for ‘potenz’ a German word which means power. We can measure from zero to 14 on this scale. Zero represents strongest acid, and 14 represents strongest base. pH is such a number which represents acidic or basic nature of a solution. More is the concentration of hydrogen ion in a solution less is its pH value. If a solution is neutral its pH value is 7. If pH is lower than 7 then solution is acidic and if pH is more than 7 then solution is basic. Normally pH can be found by using universal pH indicator paper.

Question 28.
Are salt crystals really dry? Explain.
Answer:
Copper sulphate crystals which seems to be dry contains water of crystallization. These seem to be dry hut are not. When we heat the crystals then this water is removed and colour of salt become white. When salt is made wet its colour again change to blue.

Fixed number of molecules of water present in unit formula of salt is called water of crystallization. In unit formula of copper sulphate, there are five molecules of water. Formula for hydrated copper sulphate is CuSO4. 5H2O. In Na₂CO₃.10H₂O there are 10 molecules of water.

Gypsum is another salt which contains water of crystalization. There are two molecules of water in it.
Its formula is CaSO₄.2H₂O.

Question 29.
How is washing soda prepared? Give its uses.
Answer:
Washing soda (Na₂CO₃.10H₂O) is obtained from sodium chloride. By heating soda, we get sodium carbonate. By recrystallization of sodium carbonate, washing soda is obtained. This is a basic salt.

Sodium carbonate and sodium bicarbonate are useful in several industrial processes.

Uses of washing soda :

• Sodium carbonate is used in glass, soap and paper industry.
• It is used in the manufacturing of sodium compound such as Borax.
• It is used in cleaning agent for domestic purpose.
• It is used to remove permanent hardness of water.

Question 30.
What is efflorescence? Name one compound which shows efflorescence? Explain your answer with an equation.
Answer:
The phenomenon of losing some part of water of cyrstallization into air from a crystal is called efflorescence. This phenomenon takes place on heating or some times spontaneously. Washing soda contain water of crystallization hence its formula is Na₂CO₃. 10H₂O. When it is placed in open then it loose its 9 molecules of water and single hydrate is left.
Na₂CO₃.10H₂O → Na₂CO₃.H₂O + 9H₂O

on heating it looses all of its water.
Na₂CO₃.10H₂O → Na₂CO₃ + 10H₂O

Question 31.
A baker found that a cake prepared by him is small in size and hard. Which constituent, he forgot to add, due to which cake can become soft and big. Give reason.
Answer:
Baker forgot to add baking powder. When baking powder (a mixture of sodium bicarbonate and Tartaric acid) is added to cake and on heating tartaric acid reacts with sodium bicarbonate to produce carbon dioxide. This carbon dioxide makes the cake to swell and cake becomes light. Baker, definitely forgot to add baking powder that is why cake is small and hard.

Question 32.
When bleaching powder is left open in air, then what happens?
Answer:
When bleaching powder is left open in air, then its properties change. C02 present in air reacts with it due to which calcium carbonate and chlorine gas are produced. Properties of bleaching are lost.
CaOCl₂ + CO₂ → CaCO₃ + Cl₂

Question 33.
What are the important uses of bleaching powder?
Answer:

• It is used to bleach cotton cloths, linen and wood pulp.
• It is used to disinfect drinking water and to make it free of germs.
• It is used to make chloroform.
• Unshrinkable wool is prepared using bleaching powder.
• It acts as oxidizing agent in Laboratories and in industry.

Question 34.
Name the compounds used in hospitals for supporting fractured bones in the right position. How is it prepared?
Answer:
The compound used in hospitals for supporting fractured bones in the right position is plaster of paris. It is calcium sulphate hemihydrate (CaSO₄. \(\frac{1}{2}\)H₂O). It is prepared at a temperature of 373 K by heating gypsum.

Question 35.
Write important uses of Plaster of Paris.
Answer:

• It is used in making toys, moulds, ceramic, containers etc.
• It is used for making material for decoration and statues.
• In hospitals it is used by doctors to set fractured bones and by dental doctors for creating mould to make dentures.
• Used in buildings, to give plane look to walls and ceiling.
• Material used by fire fighters.
• It is used to stop leakage of gases in Laboratories.

Question 36.
Many people complaint about gas problem in stomach. What is main reason for this? Why do they use ‘milk of magnesia’ to get relief from this?
Or
What are antacids?
Answer:
A juice is secreted in the stomach which contains enzyme pepsine and hydrochloric acid. Enzyme pepsine is active in acidic medium. When hdyrochloric acid is produced in excess quantity, then we get burning and pain in the stomach, which is known as acidity.

Those substances which are used to neutralize this acid are called antacids. Usually people take a mild base like milk of magnesia for this purpose. It neutralizes the excess acid and provide relief.

Question 37.
Idols and utensils made up of copper and brass become shiny when rubbed with lemon? Why?
Answer:
Idols and utensils made up of copper and brass become dull due to coating of copper oxide. Citric acid present in lemon react with it to form salt, which can be easily washed with water. Brass and copper surface becomes shiny.

Question 38.
For the safety of teeth what type of toothpaste should be used. Why?
Or
How does change in pH-value helps in tooth decay?
Answer:
Bacteria present in mouth produce acid by degradation of sugar and food particles. This reduces the pH value of mouth which causes tooth decay. After foods we should used basic tooth pastes to prevent tooth decay. Mild bases present in it neutralizes the excess acid. This reducing the chances of tooth decay.

Question 39.
What is the remedy for sting of Nettle plant? Write.
Answer:
Nettle is a herbaceous plant found in jungles. Its leaves have stinging hair. These hair cause painful sting if touched accidentally. This pain is due to the secretion of methanoic acid by stinging hair in the body. To get rid of this pain leaves of dock plant are rubbed on the area of sting. Leaves of dock plant have base in them. This plant often grows beside the nettle plant. It neutralizes the acidic effect and gives relief from pain.

Question 40.
What is acidic rain? How is the pH of soil can be measured?
Answer:
Some of the gases like SO₂, SO₃, NO₂ etc. present in the atmosphere gets dissolved in rain water and fall on earth in the from of acid is called acid rain. This corrodes some of the metals and marble.

pH value of soil can be measured by using paper soaked in universal indicator. This way we can know the nature of soil as acidic or basic. When pH value of rain water is less < than 5-6 then it is called acid rain. To know the pH value of soil, it is dissolved in water in a test tube and its filter is tested with universal indicator pH paper.

Question 41.
Is human life possible on venus planet?
Answer:
No, human life is not possible on venus plant the atmosphere of venus is covered with thick white and yellow clouds of sulphuric acid. If there is a rain is presence of water, it will be acidic and the existence of human life will be impossible.

Question 42.
Magnesium is treated with dil. H₂SO₄. The gas evolved is collected as shown below. Name the method used for collection of gas and the gas produced.

Answer:
Downward displacement of water. The gas produced is hydrogen.

Question 43.
Compounds such as alcohols and glucose also contain hydrogen but are not categorised as acids. Describe an activity to prove it.

Answer:
Fix two nails on a cork and place it in a 100 ml beaker. Connect thses nails to a 6 volt battery through a bulb and switch as shown in the figure.

Pour some aqueous solution of alcohol or aqueous solution of glucose in the beaker so that nails dip in it. Switch on the current. The bulb does not glow indicating that alcohol and glucose don’t dissociate in aqueous solution and hence do not produce H⁺_(aq) ions although they contain hydrogen.

Aqueous solution of alcohol or glucose does not conduct electricity

1 — Cathode
2 — Anode

Question 44.
Observe the figure and answer the following:

(i) What are 1 and 2?
Answer:
1-Soap bubble filled with hydrogen 2-Burning of hydrogen gas with a pop sound

(ii) Write down the reactions taking place in test tube.
Answer:

Question 45.
In the pH paper shown in figure given below, pH of lemon juice is 2.2 and that milk of magnesia is 10. What is its significance?

Answer:

• Lemon justice is acidic because pH is less than 7.
• Milk of magnesia is basic because pH is more than 7.

Question 46.
Which gas is being produced during reaction in the test tube? How does this gas react with Calcium Hydroxide/Lime water?

Answer:
Carbon dioxide (CO₂).

Very Short Answer Type Questions

Question 1.
What makes food sour?
Answer:
Presence of acids.

Question 2.
What is the reason of bitterness?
Answer:
Presence of bases.

Question 3.
What is the reason of acidity in stomach?
Answer:
excess of HCl acid.

Question 4.
What is the effect of acid on litmus?
Answer:
Blue litmus changes to red.

Question 5.
What are olfactory indicators?
Answer:
Some substances which change their smell in acidic or basic medium are called . olfactory indicators.

Question 6.
Give three examples of olfactory indicators.
Answer:
Chopped onions, clove coil, vanilla essence.

Question 7.
Which gas is produced when Zinc reacts with sodium hydroxide?
Answer:
Hydrogen gas.

Question 8.
Which gas is produced when metal carbonates and metal hydrogen carbonates react with acid?
Answer:
Carbon dioxide.

Question 9.
What happens when CO₂ is passed through lime water?
Answer:
Lime water turns milky.

Question 10.
Why milkiness of lime water disappear when excess of CO₂ is passed through it?
Answer:
Due to formation of Ca(HCO₃)₂ which is soluble in water.

Question 11.
Write the name and colour of the compound formed when copper oxide reacts with dilute hydrochloric acid.
Answer:
Blue-green copper chloride.

Question 12.
Which name is used for metal oxide?
Answer:
Alkaline oxide.

Question 13.
What is the nature of non-metal oxide?
Answer:
Acidic nature.

Question 14.
Why does current flow in acids?
Answer:
Due to ions.

Question 15.
Which ion is produced in acidic solution?
Answer:
Hydrogen ion (H+).

Question 16.
What is used to dry, moist gas?
Answer:
Calcium chloride.

Question 17.
How do we represent hydrogen ion?
Answer:
H⁺_(aq) or hydronium ion (HgO⁺).

Question 18.
Which ions is produced by bases in water?
Answer:
Hydroxide (OH^–) ion.

Question 19.
What is base?
Answer:
Alkalies which are soluble in base.

Question 20.
What should we do to dilute an acid?
Answer:
We should add acid to water slowly and not vice versa.

Question 21.
What is dilution?
Answer:
When we add acid or base in water, concentration of ions (HgO⁺/OH^–) per unit volume decreases, this is known as dilution.

Question 22.
What is name of mixture of various indicators?
Answer:
Universal indicator.

Question 23.
What is that which show different colour at different concen-tration of hydrogen ion in a solution?
Answer:
Universal indicator.

Question 24.
What is pH scale?
Answer:
To know the strength of H⁺ ion in a solution a scale is used known as pH scale.

Question 25.
What is p in pH?
Answer:
‘p’ means ‘potenz’.

Question 26.
What is the range of pH scale?
Answer:
0 to 14.

Question 27.
What is pH value of neutral solution?
Answer:
pH value is 7.

Question 28.
If pH value of solution is less than 7, then what does it indicate?
Answer:
Acidic solution.

Question 29.
If pH value of a solution is more than 7, then what does it indicate?
Answer:
Solution is basic.

Question 30.
What is the value on pH scale for lemon juice?
Answer:
Nearly 2.2.

Question 31.
What is the value on pH scale for pure water?
Answer:
7

Question 32.
What is the value on pH scale for milk of magnesia?
Answer:
10.

Question 33.
What is the value on pH scale for sodium hydroxide?
Answer:
Nearly 14.

Question 34.
What is pH range in which our body works?
Answer:
Our body works in the pH range of 7.0 to 7.8.

Question 35.
What is pH value of acid rain?
Answer:
It is less than 5.6.

Question 36.
In which type of river survival of aquatic animals is difficult?
Answer:
When acid rain water flows to the river.

Question 37.
What surrounds the venus planet?
Answer:
Thick white and yellow clouds of sulphuric acid.

Question 38.
Which acid is produced in our stomach?
Answer:
Hydrochloric acid.

Question 39.
What is produced in the stomach when there is indigestion.
Answer:
Excess of HCl.

Question 40.
What is used for treating excess of acid in the stomach?
Answer:
Antacids (mild bases).

Question 41.
When does tooth decay begin?
Answer:
When pH value in less than 5.5.

Question 42.
Teeth are made up of which substance?
Answer:
Calcium phosphate.

Question 43.
Why do we feel pain due to bee sting?
Answer:
Due to acid.

Question 44.
Which substance is applied on the stinging area which gives relief from pain?
Answer:
Weak base like baking soda.

Question 45.
What do the stinging hair of nettle plant secret?
Answer:
Methanoic acid.

Question 46.
What is the remedy for sting of herbaceous plant Nettle?
Answer:
Rub leaves of dock plant.

Question 47.
Which acid is there in vinegar?
Answer:
Acetic acid.

Question 48.
Which acid is there in lemon, orange?
Answer:
Citric acid.

Question 49.
Which acid is in curd and milk?
Answer:
Lactic acid.

Question 50.
What is main source of salt?
Answer:
Sea water.

Question 51.
What is exothermic reaction?
Answer:
Those chemical reactions in which heat is produced.

Question 52.
What is endothermic reaction?
Answer:
Those chemical reactions in which heat in absorbed are called endothermic reactions.

Question 53.
Solid sodium chloride does not conduct electric current, why?
Answer:
In sodium chloride, Na+ and Cl- ions are held together by strong electrostatic forces of attraction and ions can’t move freely. Hence solid sodium chloride does not conduct electric current.

Question 54.
In which state chemical reactions take place easily.
Answer:
Gaseous or liquid state.

Question 55.
What is solute?
Answer:
It is a compound, which in aqueous solution, dissociate into positive and negative ions.

Question 56.
What is a strong electrolyte?
Answer:
A compound which dissociate in water and its dissociation percentage is 30%, is called strong electrolyte.

Question 57.
What is weak electrolyte?
Answer:
A compound which dissociate in water and its dissociation percentage is less than 30% is called weak electrolyte.

Question 58.
Which acids are obtained from animals?
Answer:
Organic acids.

Question 59.
Who gave pH scale and when?
Answer:
pH scale was given by Danish Chemist Soren Sorensen in 1909.

Question 60.
Concentration of which ion is important in every Biological and many industrial processes?
Answer:
Concentration of hydrogen ion.

Question 61.
What is the reason for burn feeling in stomach and chest? How to get rid of this situation?
Answer:
When excess of hydrochloric acid is produced in stomach, then we feel burn feeling in stomach and chest. We can be relieved by taking baking soda.
NaHCO₃ + HCl → NaCl + H₂O + CO₂

Question 62.
What is baking powder?
Answer:
Baking powder is a mixture of baking soda and tartaric acid.

Question 63.
If we do not use tartaric acid in baking powder for making a cake. How will the cake taste?
Answer:
It will be bitter due to sodium carbonate.

Question 64.
Which chemicals are used in fire extinguishers?
Answer:
Sodium hydrogen carbonate and sulphuric acid.

Question 65.
Which gas is produced in soda acid fire extinguisher?
Answer:
Carbon dioxide gas.

Question 66.
Which compound is used to make water free of germs?
Answer:
Bleaching powder (CaOCl₂).

Question 67.
Name chemical name of quick lime.
Answer:
Calcium oxide (CaO).

Question 68.
Name the deliquescent present in salt.
Answer:
Magnesium chloride (MgCl₂).

Question 69.
What type of smell is given by bleaching powder?
Answer:
Smell of ehlorme gas.

Question 70.
Sometimes eyes become red after swimming in a swimming pool why?
Answer:
Due to excess of bleaching powder in water.

Question 71.
When did Egyptions used plaster of paris?
Answer:
They used it 5000 years ago.

Question 72.
How did the Egyptions prepare plaster of Paris?
Answer:
They heated Gypsum in open air.

Question 73.
What was the use of Plaster of Paris for Egyptions?
Answer:
They used to fix rocks with it as cement for their monuments.

Question 74.
What is the relation of ‘Paris’ in plaster of Paris?
Answer:
In the beginning Gypsum was obtained from Montmarti in Paris, thus paris is related with it.

Question 75.
What is heated to which temperature from preparing plaster of Paris?
Answer:
Plater of Paris is obtained from gypsum (CaSO₄.2H₂O) by heating it to 373 K.

Multiple Choice Questions:

Question 1.
pH of an acidic solution is:
(A) >7
(B) <7
(C) 7
(D) 14.
Answer:
(B) <7

Question 2.
Neutral solution has pH:
(A) 7
(B) >7
(C) < 7
(D) 14.
Answer:
(A) 7

Question 3.
Common name of NaCO₃. 10H₂O is :
(A) Bleaching powder
(B) Baking powder
(C) Plaster of Paris
(D) Washing soda.
Answer:
(D) Washing soda.

Question 4.
Acid and base react to form salt and water. This reaction is called:
(A) Washing soda.
(B) Chioro-alkali
(C) Reduction
(D) None of these.
Answer:
(D) None of these.

Question 5.
What is used for plastering fractured bones?
(A) Cement
(B) Gypsum
(C) Plaster of Paris
(D) Soda.
Answer:
(C) Plaster of Paris

Question 6.
Toothpaste used for cleaning teeth is :
(A) Acidic
(B) Neutral
(C) Basic
(D) None.
Answer:
(A) Acidic

Question 7.
A solution turns red litmus blue, its pH is :
(A) 1
(B) 4
(C) 5
(D) 10
Answer:
(D) 10.

Fill in the blanks:

Question 1.
The common name of CaOCl₂ is ______
Answer:
Bleaching powder.

Question 2.
The sodium compound used for softening hard water is ______
Answer:
Washing soda.

Question 3.
The common name of Na₂CO₃.10H₂O is ______
Answer:
Washing soda.

Punjab State Board PSEB 10th Class English Book Solutions English Grammar Simple, Complex and Compound Sentences Exercise Questions and Answers, Notes.

PSEB 10th Class English Grammar Simple, Complex and Compound Sentences

Analyse the following sentences, selecting the Principal Clause and the Noun Clause. Also, state the function of the Noun Clause.

(A)

1. That Mohan was a doctor was not known to me.
2. Where the boys will stay is not yet known.
3. That Mohan will stand first is certain.
4. What cannot be cured must be endured.
5. Why the thief did not take away the gold is a mystery.
Answer:

(B)

1. Ask Asha if Papa has come.
2. Can you tell me why Mohan is absent today?
3. I know that she loves music.
4. Tell me why you hate me.
5. I had never thought that your brother was so lazy.
Answer:

(C)

1. My fear was that Mohan would reach late.
2. Life is what you make it.
3. It seems that it will rain soon.
4. Things are not what they appear to be.
5. My firm belief is that Harpreet will stand first.
Answer:

(D)

1. Aren’t you ashamed of what you have done ?
2. She must listen to what her teacher says.
3. She agrees to whatever Mohan says.
4. There is no truth in what is stated by Asha.
5. Your success depends on how hard you work.
Answer:

(E)

1. The statement that all students will get two rasgullas every day is not true.
2. The news that Sania Mirza has won is correct.
3. The story that Ram Nath kidnapped his own nephew has been confirmed.
4. It is true that boys are generally taller than girls.
5. The fact that Harbhajan is a cricketer is known to all.
Answer:

(F)

1. Finding that the situation was getting worse, the police opened fire.
2. I went to the manager finding that I had been cheated by the company.
3. Thinking that he was a stranger to the city, I helped him.
4. Mohan left the meeting saying that he could not compromise with his principles.
5. We attacked the robber knowing that he was desperate to do anything.
Answer:

(G)

1. I want to confirm if he has a hand in it.
2. We asked him to explain what he had done.
3. She wants to know how the quarrel stafted.
4. I want to know for certain if you helped the thief.
5. I want to know why he stole the money.
Answer:

Pick out the Adjective Clauses from the following sentences and state the function of each.

1. She is the girl who helped me.
2. He killed the snake that bit his wife.
3. The habits that are formed in early age are difficult to break.
4. The furniture he gave us was worth nothing.
5. He who helps others is sure to be helped by God.
6. Such students as work hard are liked by all.
7. He who has no money has no friends.
8. This is the doctor who treated me.
9. This is the reason why she refused to marry Mohan.
10. There was not a single worker who did not go on strike.
11. I gave him such advice as was very useful.
12. Time once lost is lost for ever.
13. This is the school that the President visited.
14. I remember the village where I was born.
15. He is the man who displayed those magic tricks.
Answer:
The Adjective Clauses are :
1. ‘who helped me’ – Adjective Clause qaualifying the noun ‘girl’
2. ‘that bit his wife’ Adjective Clause qualifying the noun ‘snake?
3. ‘that are formed in early age’ – Adjective Clause qualifying the noun ‘habits’.
4. ‘(that) he gave us’ – Adjective Clause qualifying the noun ‘furniture’.
5. ‘who helps others’ – Adjective Clause qualifying the pronoun ‘he’.
6. as work hard. Adjective Clause qualifying the noun ‘students’.
7. ‘who has no money’ – Adjective Clause qualifying the pronoun ‘he’!
8. ‘who treated me’ – Adjective Clause qualifying the noun ‘doctor’
9. ‘why she refused to marry Mohan’ – Adjective Clause qualifying the ‘noun reason’
10. ‘who did not go on strike’ – Adjective Clause qualifying he noun ‘worker’.
11. as was very useful – Adjective Clause qualifying the noun ‘advice’.
12. (that is) once lost – Adjective Clause qualifying the noun ‘time’.
13. that the President visited – Adjective Clause qualifying the noun ‘school’.
14. where I was born – Adjective Clause qualifying the noun ‘village’.
15. ‘who displayed those magic tricks’ – Adjective Clause qualifying the noun ‘man’.

Pick out the Adverb Clause from each of the following sentences and state the function of each.

(A)

1. Look before you leap.
2. No sooner did the train stop than the boys jumped out.
3. Strike the iron while it is hot.
4. The plane had landed before I reached the airport.
5. As long as you work hard, we will not throw you out.
Answer:
1. before you leap’—Adverb clause showing time.
2. No sooner did the train stop? Adverb clause showing time.
3. While it is hot’ –Adverb clause showing time.
4. before I reached the airport-Adverb clause showing time.
5. As long as you work hard-Adverb clause showing time.

(B)

1. The boat sailed where the wind took it.
2. Send the scooter where it came from.
3. I’ll go with you wherever you go.
4. He gets into trouble wherever he goes.
5. Buy this book wherever you find it.
Answer:
1. where the wind took it-Adverb clause showing place.
2. where it came from –Adverb clause showing place.
3. ‘wherever you goʻ–Adverb clause showing place.
4. ‘wherever he goes’-Adverb clause showing place.
5. wherever you find it-Adverb clause showing place.

(C)

1. Since you are late, I cannot let you in.
2. You will pass the examination because you are working hard.
3. I respect her because she is kind to me.
4. I am glad that you have acted honestly.
5. He is afraid that he may be punished.
Answer:
1. “Since you are late’-Adverb clause showing reason.
2. because you are working hard-Adverb clause showing reason.
3. because she is kind to me-Adverb clause showing reason.
4. that you have acted honestly–Adverb clause showing reason.
5. that he may be punished-Adverb clause showing reason.

(D)

1. I’ll help her provided she works hard.
2. If Mohan comes late, the teacher will punish him.
3. He won’t get the book unless he comes to me.
4. If it rains, we shall stay indoors.
5. If the bus is late, we will take a taxi.
Answer:
1. ‘provided she works hard’-Adverb clause showing condition.
2. If Mohan comes late’-Adverb clause showing condition.
3. ‘unless he comes to me-Adverb clause showing condition.
4. If it rains’-Adverb clause showing condition..
5. If the bus is late-Adverb clause showing condition.

(E)

1. Mohan is as active as he is hard-working.
2. As you sow, so shall you reap.
3. Dress as you like.
4. I know French better than you do.
5. He behaves as if he was mad.
Answer:
1. as he is hard-working-Adverb clause showing extent.
2. As you sow-Adverb clause showing manner.
3. as you like’-Adverb clause showing manner.
4. better than you do’-Adverb clause showing comparison.
5. ‘as if he was mad-Adverb clause showing manner.

(F)

1. No matter how hard up she is, she cannot be mean.
2. We shall go ahead with this business even if we suffer a great loss.
3. Although he tried hard, he did not succeed.
4. You cannot pass however hard you may try.
5. Papa did not agree though I requested him time and again.
Answer:
1. No matter how hard up she is’ — Adverb clause showing contrast.
2. ‘even if we suffer a great loss — Adverb clause showing contrast.
3. Although he tried hard’ – Adverb clause showing contrast.
4. however hard you may try – Adverb clause showing contrast.
5. though I requested him time and again’ – Adverb clause showing contrast.

Sentences तीन प्रकार के होते हैं :

1. Simple Sentence (सरल वाक्य)-जिस वाक्य की केवल एक ही Clause हो, उसे Simple Sentence कहा जाता है; जैसे
1. The boy broke his leg.
2. She washed her clothes.
3. Mohan stood first in his class.
4. I wrote a letter to my father.

2. Compound Sentence (संयुक्त वाक्य) -जिस वाक्य में दो या दो से अधिक अनाश्रित Clauses हों, उसे Compound Sentence कहा जाता है, उदाहरण के रूप में
1. Sita saw Rama and she became happy.
2. You must work hard or you will fail.
3. Many were called, but few were chosen.
4. The sun rose and the fog disappeared.
Compound Sentence की प्रत्येक Clause को Co-ordinate Clause कहा जाता है।

3. Complex Sentence (मिश्रित वाक्य) – जिस वाक्य में एक मुख्य वाक्य (Principal
Clause) हो तथा एक या एक से अधिक आश्रित वाक्य (Subordinate Clauses) हों, उसे Complex Sentence कहा जाता है।
Principal Clause को Main Clause भी कहा जाता है। Subordinate Clause को Dependent Clause भी कहा जाता है।

Kinds Of Subordinate Clauses

Subordinate Clauses तीन प्रकार की होती हैं :
1. Noun Clause
2. Adjective Clause
3. Adverb Clause

1. Noun Clause : किसी Complex Sentence में जो पद एक संज्ञा (Noun) का कार्य कर रहा हो, उसे Noun Clause कहा जाता है।
निम्नलिखित वाक्यों में तिरछे छपे हुए शब्द-समूह Noun Clause बनाते हैं :
1. That John was a thief was not known to me.
2. He was told that he must not be late again.
3. Learning that my brother had received serious injuries, I left for Shimla.

2. Adjective Clause : किसी Complex Sentence में जो पद किसी विशेषण (Adjective) का कार्य कर रहा हो, उसे Adjective Clause कहा जाता है। निम्नलिखित वाक्यों में तिरछे छपे हुए शब्द-समूह Adjective Clause बनाते हैं :
1. The company that supplied goods has failed.
2. The house where my brother lives has been sold.
3. The complaint which he made against me is false.

3. Adverb Clause : किसी Complex Sentence में जो पद किसी क्रिया-विशेषण (Adverb) का कार्य कर रहा हो, उसे Adverb Clause कहा जाता है। निम्नलिखित वाक्यों में तिरछे छपे हुए. शब्द-समूह Adverb Clause बनाते हैं :
1. When the cat is away, the mice will play.
2. Where there is a will, there is a way.
3. You should act as the doctor advises you.
अब हम Complex Sentence के सम्बन्ध में प्रत्येक प्रकार की Clause का विस्तारपूर्वक अध्ययन करेंगे।

Noun Clause

Noun Clause (संज्ञा उपवाक्य)- जिस उपवाक्य का प्रयोग प्रधान वाक्य के किसी शब्द के साथ सम्बन्ध रखने वाली संज्ञा के रूप में किया जाये, उसे Noun Clause कहा जाता है। यह संज्ञा निम्नलिखित अवस्थाओं में हो सकती हैं :
1. Subject to a Verb.
2. Object to a Verb.
3. Object to a Participle.
4. Object to an Infinitive.
5. Object to a Preposition.
6. Complement to a Verb.
7. In apposition to a Noun.
8. In apposition to a Pronoun.

अब हम प्रत्येक प्रकार की Noun Clause का विस्तारपूर्वक अध्ययन करेंगे।

1. Subject to a Verb.
1. How she reached there is a mystery.
2. That Vinod was a thief was not known to me.
3. Whether he did so is doubtful.

2. Object to a Verb.
1. He was told that he must not be late again.
2. He asked her how old she was.
3. I always do whatever is right.

3. Object to a Participle.
1. He went there thinking that he might be able to help him.
2. Seeing that the child was drowning, I jumped into the canal.
3. Fearing that he should be late, he ran all the way to the station.

4. Object to an Infinitive.
1. I was shocked to hear that his only son had died.
2. I want to know what you are doing here.
3. He came to ask if I was going to school.

5. Object to a Preposition.
1. Listen to what your teacher says.
2. The horse will sell for what it costs.
3. They were arguing about who should do it.

6. Complement to a Verb.
1. The fact is that he knows nothing
2. We are what we think.
3. It seems that he will be a great man one day.

नोट : be (is, am, are, was, were, been), seem, look, appear, become, आदि Linking Verbs के बाद प्रयुक्त होने वाले शब्द अथवा पद Complement कहलाते हैं।

7. In apposition to a Noun.
1. They took a vow that they would die for their motherland.
2. He fufilled his promise that he would help me.
3. The rumour that war has broken out is not true.

8. In apposition to the Pronoun “it.
1. It is true that he is honest.
2. See to it that the boy is not hurt.
3. It is unfortunate that he has failed.

Adjective Clause

Adjective Clause (विशेषण उपवाक्य)-जो उपवाक्य प्रधान वाक्य के किसी शब्द के सम्बन्ध में विशेषण का काम कर रहा हो, उसे Adjective Clause कहा जाता है। Adjective Clause दो अवस्थाओं में हो सकती है।

1. Qualifying a Noun.
2. Qualifying a Pronoun. अब हम प्रत्येक प्रकार की Adjective Clause का विस्तारपूर्वक अध्ययन करेंगे।

1. Qualifying a Noun.
1. The company that supplied the goods has failed.
2. The house where your brother lived has been sold.
3. The complaint he made against me is false.

2. Qualifying a Pronoun.
1. There was none but wept.
2. He that climbs too high is liable to fall.
3. All that glitters is not gold.

Adjective Clause के प्रयोग के सम्बन्ध में ध्यान रखने योग्य कुछ ज़रूरी बातें :

(1) Adjective clause को Principal clause के साथ जोड़ने के लिए प्रायः निम्नलिखित sentence linkers का प्रयोग किया जाता है

(a) Relative Pronouns : Who, whom, whose (+ noun), that, which, as, but.
1. The boys who are playing there are my students.
2. He is the man whom I gave my book.
3. She is the girl whose book was stolen.
4. You can take the pen which you like.
5. He has cut down the tree that grew in your field.
6. Nothing but hard work pays in the long run.

(b) Relative Adverbs : When, where, why.
1. We saw the house where he was born.
2. He met me on the day when I was leaving for Mumbai.
3. I told her the reason why she had failed.

(2) Who, whom तथा whose का प्रयोग मनुष्य-जाति के लिए किया जाता है; जैसे
1. He who works hard will succeed.
2. She is the girl whom I gave my books.
3. There stands the boy whose purse has been stolen.

(3) Whose का प्रयोग कई बार निर्जीव वस्तुओं के लिए भी कर लिया जाता है; जैसे
1. Draw a triangle whose sides are equal.
2. This is the house whose owner has died.

(4) Which का प्रयोग जानवरों और निर्जीव वस्तुओं के लिए किया जाता है; जैसे
1. The dog which bit him has been killed.
2. This is the watch which I wanted to buy.

(5) That का प्रयोग मनुष्य-जाति के लिए, जानवरों के लिए और निर्जीव वस्तुओं के लिए भी किया जा सकता हैजैसे
1. Happy is the man that (= who) is honest.
2. This is the house that (= which) I wanted to buy.
3. The man that (= whom) we were looking for has arrived.

किन्तु यह बात ध्यान रखने योग्य है कि that का प्रयोग whose, of which, in which, to whom, आदि के स्थान पर नहीं किया जा सकता है। यदि Relative Pronoun से पूर्व-स्थित संज्ञा बिना बताए ही स्पष्ट (understood) हो और वह नपुंसक लिंग की हो, तो Relative Pronoun के रूप में which की बजाए what का प्रयोग किया जाता है। जैसे

1. I cannot tell you what has happened. [what = the thing which]
2. I have brought what he wanted. [what = the thing(s) which]

Adverb Clause

Adverb Clause किया विशेषण उपवाक्य : जो उपवाक्य प्रधान वाक्य के किसी सब्द के सम्बन्ध में क्रिया-विशेषण का काम कर रहा हो, उसे Adverb Clause कहा जाता है। यह विशेषता निम्नलिखित
1. Time
2. Place
3. Purpose
4. Reason
5. Condition
6. Result
7. Comparison
8. Contrast
9. Manner
10. Extent.

अब हम प्रयेक प्रकार की Adverb Clause का विस्तारपूर्वक अध्ययन करेंगे

1. Showing Time.
1. When the cat is away, the mice will play.
2. Wait here till I return.
3. As soon as she saw her father, she began to cry.

2. Showing Place.
1. I went where he led me.
2. You can go wherever you like.
3. Where there is a will, there is a way.

3. Showing Purpose.
1. People work so that they may earn a living.
2. He died in order that freedom might live.
3. He ran fast lest he should miss the train.

4. Showing Reason.
1. He is unable to attend school because he is ill.
2. I cannot see you as I am not keeping well.
3. Since you are over fourteen, you will have to pay full fare.

5. Showing Condition.
1. If you work hard, you will succeed.
2. I will not go there unless you accompany me.
3. In case you come to me, I will help you.

6. Showing Result (or Effect).
1. It was so dark that we could hardly see a foot before us.
2. He is so weak that he cannot move about.
3. He is such a dull boy that he cannot understand it.

7. Showing Comparison.
1. He is as intelligent as his brother.
2. You are stronger than I am.
3. I can run faster than you.

8. Showing Contrast.
1. Although he is poor, he is honest.
2. The teacher gave him pass marks, though he deserved less.
3. Weak as he is, he does his duty.

9. Showing Manner.
1. You should follow me as I follow him.
2. He ran as if he were mad.
3. You should act as the doctor advises.

10. Showing Extent.
1. So far as I know, he has left the place.
2. The more you have, the more you want.
3. The higher you go, the cooler it is.