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# Lakhmir Singh solutions for Class 10 Chemistry (Science) chapter 2 - Acids, Bases and Salts [Latest edition]

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## Chapter 2: Acids, Bases and Salts

### Lakhmir Singh solutions for Class 10 Chemistry (Science) Chapter 2 Acids, Bases and Salts [Pages 0 - 69]

Q 1.1 | Page 66

What colour do the following indicators turn when added to a base or alkali (such as sodium hydroxide)?
(a) methyl orange

Q 1.2 | Page 66

What colour do the following indicators turn when added to a base or alkali (such as sodium hydroxide)?

litmus

Q 1.3 | Page 66

What colour do the following indicators turn when added to a base or alkali (such as sodium hydroxide)?

red cabbage extract

Q 2.1 | Page 66

What colours do the following indicators turn when added to an acid (such as hydrochloric acid)?

litmus

Q 2.2 | Page 66

What colours do the following indicators turn when added to an acid (such as hydrochloric acid)?
methyl orange

Q 3 | Page 66

Name an indicator which is red in acid solution but turns blue in basic solution.

Q 4 | Page 66

Name an indicator which is pink in alkaline solution but turns colourless in acidic solution.

Q 5 | Page 66

When a solution is added to a cloth strip treated with onion extract, then the smell of onion cannot be detected. State whether the given solution contains an acid or a base.\

Q 6 | Page 66

When a solution is added to vanilla extract, then the characteristic smell of vanilla cannot be detected. State whether the given solution is an acid or a base.

Q 7 | Page 66

How will you test for the gas which is liberated when hydrochloric acid reacts with an active metal?

Q 8 | Page 66

Name the gas evolved when dilute HCl reacts with sodium hydrogencarbonate. How is it recognised?

Q 9 | Page 66

Give the names and formulae of two strong acids and two weak acids.

Q 10.1 | Page 66

Name one natural source of the following acids:

Citric acid

Q 10.2 | Page 66

Name one natural source of the following acids:
Oxalic acid

Q 10.3 | Page 66

Name one natural source of  the following acids:
Lactic acid

Q 10.4 | Page 66

Name one natural source of the following acids:
(d) Tartaric acid

Q 11 | Page 66

Name one animal and one plant whose stings contain formic acid (or methanoic acid).

Q 12 | Page 66

How is the concentration of hydronium ions (H3O+) affected when a solution of an acid is diluted?

Q 13.1 | Page 66

Write word equations and then balanced equations for the reactions taking place when:
(1) dilute sulphuric acid reacts with zinc granules.

Q 13.2 | Page 66

Write word equations and then balanced equations for the reactions taking place when:

dilute hydrochloric acid reacts with magnesium ribbon.

Q 13.3 | Page 66

Write word equations and then balanced equations for the reactions taking place when:

dilute sulphuric acid reacts with aluminium powder.

Q 13.4 | Page 66

Write word equations and then balanced equations for the reactions taking place when:

dilute hydrochloric acid reacts with iron filings.

Q 14.1 | Page 67

Complete and balance the following chemical equations:
Zn  (s)  + HCI   (aq) →

Q 14.2 | Page 67

Complete and balance the following chemical equations

Na2 CO3 (s) + HCI (aq) →

Q 14.3 | Page 67

Complete and balance the followingchemicalequations:

NaHCO3 (S) + HCI (aq) →

Q 14.4 | Page 67

Complete and balance the following chemical equations:

NaOH  (aq)  HCI  (aq)→

Q 14.5 | Page 67

Complete and balance the following chemical equations:

CuO (s) +  HCI (aq) →

Q 15.1 | Page 67

Fill in the blank in the following sentences:

Acids have a ..........................taste and they turn..........................litmus to..........................

Q 15.2 | Page 67

Fill in the blank in the following sentences:

Substances do not show their acidic properties without.......................... .

Q 15.3 | Page 67

Fill in the blank in the following sentences:

Acids produce.......................... ions on dissolving in water.

Q 15.4 | Page 67

Fill in the blank in the following sentences:

Those substances whose smell (or odour) changes in acidic or basic solution are called .......................... indicators.

Q 15.5 | Page 67

Fill in the blank in the following sentences:

Onion and vanilla extract are..........................indicators.

Q 16.1 | Page 67

What is an indicator? Name three common indicators.

Q 16.2 | Page 67

Name the acid-base indicator extracted from lichen.

Q 16.3 | Page 67

What colour does the turmeric paper turn when put in an alkaline solution?

Q 17 | Page 67

What is an olfactory indicator?

Q 17 | Page 67

Name two olfactory indicators?

Q 17 | Page 67

What is the effect of adding sodium hydroxide solution to these olfactory indicators?

Q 18.1 | Page 67

What happens when an acid reacts with a metal?

Q 18.1 | Page 67

Give chemical equation of the reaction involved.

Q 18.2 | Page 67

Which gas is usually liberated when an acid reacts with a metal?

Q 18.2 | Page 67

How will you test for the presence of this gas?

Q 19 | Page 67

While diluting an acid, why is it recommended that the acid should be added to water and not water to the acid?

Q 20 | Page 67

What happens when an acid reacts with a metal hydrogencarbonate? Write equation of the reaction which takes place.

Q 21.1 | Page 67

What happens when dilute hydrochloric acid is added to sodium carbonate? Write a balanced chemical equation of the reaction involved.

Q 21.2 | Page 67

Which gas is liberated when dilute hydrochloric acid reacts with sodium carbonate?

Q 21.2 | Page 67

How will you test for the presence of this gas?

Q 22.1 | Page 67

What happens when an acid reacts with a base?

Q 22.1 | Page 67

Explain by taking the example of hydrochloric acid and sodium hydroxide. Give equation of the chemical reaction which takes place. What is the special name of such a reaction?

Q 23 | Page 67

What happens when an acid reacts with a metal oxide? Explain with the help of an example. Write a balanced equation for the reaction involved.

Q 24.1 | Page 67

What are organic acids and mineral acids?

Q 24.2 | Page 67

Give two examples each of organic acids and mineral acids.

Q 24.3 | Page 67

State some of the uses of mineral acids in industry.

Q 25 | Page 67

What is meant by strong acids and weak acids? Classify the following into strong acids and weak acids:

HCI,  CH3  COOH,   H2 SO 4,   HNO3,  H2 CO3 , H2 SO3

Q 26 | Page 67

Why do HCl, H2SO4, HNO3, etc., show acid character in aqueous solutions while solutions of compounds like C6H12O6 (glucose) and C2H5OH (alcohol) do not show acidic character?

Q 27 | Page 67

What is a neutralisation reaction?

Q 27 | Page 67

Explain with an example. Give the chemical equation of the reaction which takes place.

Q 28 | Page 67

Why should curd and other sour foodstuffs (like lemon juice, etc.) not be kept in metal containers (such as copper and brass vessels)?

Q 29.1 | Page 67

What is produced if an acid is added to a base?

Q 29.2 | Page 67

Why does dry HCl gas not change the colour of dry litmus paper?

Q 29.3 | Page 67

What colour does phenolphthalein indicator turn when added to an alkali (such as sodium hydroxide)?

Q 30.1 | Page 67

Why do acids not show acidic behaviour in the absence of water?

Q 30.2 | Page 67

Why does an aqueous solution of an acid conduct electricity?

Q 30.3 | Page 67

Why does distilled water not conduct electricity whereas rain eater does?

Q 31.1 | Page 68

What happens when an acid reacts with a metal carbonate? Explain with the help of an example. Write chemical equation of the reaction involved.

Q 31.2 | Page 68

What happens when carbon dioxide gas is passed through lime water for a short time?

Write equations of the reactions involved.

Q 31.2

What happens when carbon dioxide gas is passed through lime water for a considerable time ?
Write equations of the reactions involved.

Q 32 | Page 68

With the help of labelled diagrams, describe an activity to show that acids produce ions only in aqueous solutions.

Q 33.1 | Page 68

Which element is common to all acids?

Q 33.2 | Page 68

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

Q 34 | Page 68

10 mL of a solution of NaOH is found to be completely neutralised by 8 mL of a given solution of HCl. If we take 20 mL of the same solution of NaOH, the amount of HCl solution (the same solution as before) required to neutralise it will be:
(a) 4 mL
(b) 8 mL
(c) 12 mL
(d) 16 mL

Q 35 | Page 68

Which of the following types of medicine is used for treating indigestion caused by over-eating?
(a) antibiotic
(b) analgesic
(c) antacid
(d) antiseptic

Q 36 | Page 68

A solution reacts with marble chips to produce a gas which turns lime water milky. The solution contains:
(a) Na2SO4
(b) CaSO4
(c) H2SO4
(d) K2SO4

Q 37 | Page 68

One of the following is not an organic acid. This is:
(a) ethanoic acid
(b) formic acid
(c) citric acid
(d) carbonic acid

Q 38 | Page 68

The property which is not shown by acids is:
(a) they have sour taste
(b) they feel soapy
(c) they turn litmus red
(d) their pH is less than seven

Q 39 | Page 68

The indicators which turn red in acid solution are:
(a) turmeric and litmus
(b) phenolphthalein and methyl orange
(c) litmus and methyl orange
(d) phenolphthalein and litmus

Q 40 | Page 68

The discomfort caused by indigestion due to overeating can be cured by taking:
(a) vinegar
(b) lemon juice
(c) baking soda
(d) caustic soda

Q 41 | Page 68

The property which is common between vinegar and curd is that they:
(a) have sweet taste
(b) have bitter taste
(c) are tasteless
(d) have sour taste

Q 42 | Page 68

The indicator which produces a pink colour in an alkaline solution is:
(a) methyl orange
(b) turmeric paper
(c) phenolphthalein
(d) litmus paper

Q 43 | Page 68

A solution reacts with zinc granules to give a gas which burns with a 'pop' sound. The solution contains:
(a) Mg(OH)2
(b) Na2CO3
(c) NaCl
(d) HCl

Q 44 | Page 68

When a piece of limestone reacts with dilute HCl, a gas X is produced. When gas X is passed through lime water then a white precipitate Y is formed. On passing excess of gas X, the white precipitate dissolves forming a soluble compound Z.
(a) What are X, Y and Z?
(b) Write equations for the reactions which take place:
(i) when limestone reacts with dilute HCl
(ii) when gas X reacts with lime water to form white precipitate Y
(iii) when excess of gas X dissolves white precipitate Y to form a soluble compound Z

Q 45 | Page 68

If someone is suffering from the problem of acidity after overeating, which of the following would you suggest as remedy?
Lemon juice, Vinegar, Banking soda solution

Q 46.1 | Page 69

Write a balanced chemical equation of the reaction which takes place.

Q 46.2 | Page 69

On adding dilute hydrochloric acid to copper oxide powder, the solution formed is blue-green.
Predict the new compound formed which imparts a blue-green colour to solution.

Q 46.3 | Page 69

On adding dilute hydrochloric acid to copper oxide powder, the solution formed is blue-green.
On the basis of the above reaction, what can you say about the nature of copper oxide?

Q 47.1 | Page 69

A white shirt has a yellow stain of curry. When soap is rubbed on this shirt during washing, the yellow stain turns reddish-brown. On rinsing the shirt with plenty of water, the reddish-brown stain turns yellow again.

Name the natural indicator present in curry stain.

Q 47.2 | Page 69

A white shirt has a yellow stain of curry. When soap is rubbed on this shirt during washing, the yellow stain turns reddish-brown. On rinsing the shirt with plenty of water, the reddish-brown stain turns yellow again.

Explain the changes in colour of this indicator which take place during washing and rinsing the shirt.

Q 47.3 | Page 69

A white shirt has a yellow stain of curry. When soap is rubbed on this shirt during washing, the yellow stain turns reddish-brown. On rinsing the shirt with plenty of water, the reddish-brown stain turns yellow again.

What is the nature of soap (acidic/basic) as shown by the indicator present in curry stain?

Q 48 | Page 69

You have been provided with three test-bubes. One  of these test-tubes contains distilled water and the other two contain an acidic and a basic solution respectively. If you are given only blue litmus paper, how will you identify the contents of each test-tube?

Q 49 | Page 69

A substance X which is used as an antacid reacts with dilute hydrochloric acid to produce a gas Y which is used in one type of fire-extinguisher. Name the substance X and gas Y. Write a balanced equation for the chemical reaction which takes place.

Q 50 | Page 69

How is the neutralisation of a carbonate with an acid different from the neutralisation of an oxide or a hydroxide?

Q 51.1 | Page 69

What happens to the H+ ions, of the solution, when an acid is neutralised?

Q 51.2 | Page 69

What happens to temperature of the solution, when an acid is neutralised?

### Lakhmir Singh solutions for Class 10 Chemistry (Science) Chapter 2 Acids, Bases and Salts [Pages 0 - 83]

Q 1.1 | Page 79

Name the gas evolved when zinc granules are treated/heated with:

hydrochloric acid solution

Q 1.2 | Page 79

Name the gas evolved when zinc granules are treated/heated with:

sodium hydroxide solution

Q 2 | Page 79

What is the common name of water soluble bases?

Q 3 | Page 79

What is common in all the water soluble bases (or alkalis)?

Q 4 | Page 79

Why does tooth decay start when the pH of mouth is lower than 5.5?

Q 5 | Page 79

What is the pH of a neutral solution?

Q 6 | Page 79

Which is more acidic : a solution of pH = 2 or a solution of pH = 6?

Q 7 | Page 79

hich is more basic (or more alkaline) : a solution of pH = 8 or a solution of pH = 11?

Q 8 | Page 79

Name the scientist who developed the pH scale.

Q 9 | Page 79

Name the indicator which can give us an idea of how strong or weak an acid or base is.

Q 10 | Page 79

The pH of soil A is 7.5 while that of soil B is 4.5. Which of the two soils, A or B, should be treated with powdered chalk to adjust its pH and why?

Q 11 | Page 79

What is the name of the indicator which can be used for testing the pH of a solution?

Q 12 | Page 79

What colour will universal indicator show if you add it to the following substances?
(a) potassium hydroxide, pH = 12
(b) soda water, pH = 5
(c) sulphuric acid, pH = 2

Q 13 | Page 79

A beaker of concentrated hydrochloric acid has a pH of 1. What colour will full range universal indicator turn if it is added to this beaker? Is it a strong or a weak acid?

Q 14 | Page 79

Two solutions X and Y are tested with universal indicator. Solution X turns orange whereas solution Y turns red. Which of the solutions is a stronger acid?

Q 15 | Page 79

Two solutions A and B have pH values of 3.0 and 9.5 respectively. Which of these will turn litmus solution from blue to red and which will turn phenolphthalein from colourless to pink?

Q 16 | Page 79

Two drinks P and Q gave acidic and alkaline reactions, respectively. One has a pH value of 9 and the other has a pH value of 3. Which drink has the pH value of 9?

Q 17 | Page 79

Two solutions X and Y have pH = 4 and pH = 8, respectively. Which solution will give alkaline reaction and which one acidic?

Q 18.1 | Page 79

Fill in the following blank with suitable words:

Acids have a pH...........than 7.

Q 18.2 | Page 79

Fill in the following blank with suitable words:

Alkalis have a pH.............. than 7.

Q 18.3 | Page 79

Fill in the following blank with suitable words:

Neutral substances have a pH of ................

Q 18.4 | Page 79

Fill in the following blank with suitable words:

The more acidic a solution, the ................. the pH.

Q 18.5 | Page 79

Fill in the following blank with suitable words:

The more alkaline a solution, the............... the pH.

Q 19 | Page 79

Fresh milk has a pH of 6. When it changes into curd (yogurt), will its pH value increase or decrease? Why?

Q 20.1 | Page 79

What is a universal indicator? For what purpose is it used?

Q 20.2 | Page 79

How does a universal indicator work?

Q 20.3 | Page 79

Water is a neutral substance. What colour will you get when you add a few drops of universal indicator to a test-tube containing water?

Q 21.1 | Page 79

Which chemical is injected into the skin of a person during an ant's sting?

How can the effect of these stings be neutralised?

Q 21.2 | Page 79

Which chemical is injected into the skin of a person during the nettle leaf hair sting?
How can the effect of these stings be neutralised?

Q 22.1 | Page 80

Explain the pH change as the cause of tooth decay. How can tooth decay caused by pH change be prevented?

Q 22.2 | Page 80

Explain how pH change in the lake water can endanger the lives of aquatic animals (like fish). What can be done to lessen the danger to the lives of aquatic animals in the lake?

Q 23.1 | Page 80

What happens during a bee sting? What is its remedy?

Q 23.2 | Page 80

What happens during a wasp sting? What is its remedy?

Q 24.1 | Page 80

Why is it wrong to treat a bee sting with vinegar?

Q 24.2 | Page 80

Why is it wrong to treat a wasp sting with baking soda solution?

Q 25 | Page 80

What does the pH of a solution signify? Three solution A, B and C have pH values of 6, 4 and 10 respectively. Which of the solutions is highly acidic?

Q 25.2 | Page 80

A farmer has found that the pH of soil in his fields is 4.2. Name any two chemical materials which he can mix with the soil to adjust its pH.

Q 26.1 | Page 80

The pH values of six solutions A to F are given below:

A = 0, B = 11, C = 6, D = 3, E = 13, F = 8

Which of the above solutions are (i) acids (ii) alkalis?

Q 26.2 | Page 80

(b) Name the acid or alkalis used to make (i) car batteries (ii) explosives (iii) soaps (iv) fertilisers.

Q 27.1 | Page 80

The pH of a cold drink is 5. What will be its action on blue and red litmus solutions?

Q 27.2 | Page 80

The pH values of three acids A, B and C having equal molar concentrations are 5.0, 2.8 and 3.5 respectively. Arrange these acids in order of the increasing acid strengths.

Q 28 | Page 80

Under what soil conditions do you think a farmer would treat the soil of his fields with quicklime (calcium oxide), or slaked lime (calcium hydroxide) or chalk (calcium carbonate)?

Q 29 | Page 29

Which acid is produced in our stomach? What happens if there is an excess of acid in the stomach? How can its effect be cured?

Q 30 | Page 80

The soil in a field in highly acidic. Name two materials which can be added to this soil to reduce its acidity. Give the reason for your choice.

Q 31 | Page 80

What is meant by strong bases and weak bases? Classify the following into strong bases and weak bases:
NH4OH, Ca(OH)2, NaOH, KOH, Mg(OH)2

Q 32.1 | Page 80

What ions are present in the solutions of following substances? (write the symbols only)
Hydrochloric acid

Q 32.2 | Page 80

What ions are present in the solutions of following substances? (write the symbols only)

Nitric acid

Q 32.3 | Page 80

What ions are present in the solutions of following substances? (write the symbols only)

Sulphuric acid

Q 32.4 | Page 80

What ions are present in the solutions of following substances? (write the symbols only)

Sodium hydroxide

Q 32.5 | Page 80

What ions are present in the solutions of following substances? (write the symbols only)

Potassium hydroxide

Q 32.6 | Page 80

What ions are present in the solutions of following substances? (write the symbols only)

Magnesium hydroxide

Q 33.1 | Page 80

What would you expect the pH of pure water to be?

Q 33.2 | Page 80

What colour would the universal indicator show in an aqueous solution of sugar? Why?

Q 33.3 | Page 80

A sample of rain water turned universal indicator paper yellow. What would you expect it pH to be? Is it a strong or a weak acid?

Q 34

Name two common antacids.

Q 34.1 | Page 80

What do you think will be the pH in the stomach of a person suffering from indigestion: less than 7 or more than 7?

Q 34.2 | Page 80

What do you think will be the pH of an antacid solution: less than 7 or more than 7?

Q 34.3 | Page 80

How does an antacid work?

Q 34.4 | Page 80

Name two common antacids.

Q 35 | Page 80

Separate the following into substances having pH values above and below 7. How do these influence litmus paper?
(i) Lemon juice
(ii) Solution of washing soda
(iii) Toothpaste
(iv) Vinegar
(v) Stomach juices

Q 36.1 | Page 80

Do basic solutions also have H+ (aq) ions? If yes, then why are these basic?

Q 36.2 | Page 80

When a solution becomes more acidic, does the pH get higher or lower?

Q 37.1 | Page 80

Define an acid and a base. Give two examples of each.

Q 37.2 | Page 80

Give the names and formulae of two strong bases and two weak bases.

Q 37.3 | Page 80

What type of ions is formed when an acid is dissolved in water?

Q 37.3 | Page 80

What type of ions  is formed:
when a base (or alkali) is dissolved in water?

Q 37.4 | Page 80

Write the neutralisation reaction between acids and bases in terms of the ions involved.

Q 37.5 | Page 80

Write any two important uses of bases.

Q 38.1 | Page 81

Name the gas evolved when zinc granules are treated/heated with:

sodium hydroxide solution

Q 38.2 | Page 81

What happens when bases react with non-metal oxides? Explain with the help of an example. What does this reaction tell us about the nature of non-metal oxides?

Q 39.1 | Page 81

What effect does the concentration of H+ (aq) ions have on the nature of a solution?

Q 39.2 | Page 80

What effect does the concentration of OH ions have on the nature of a solution?

Q 39.3 | Page 81

Someone put some universal indicator paper into vinegar. The pH is 3. What does this tell you about the vinegar?

Q 39.4 | Page 81

Someone put some universal indicator paper onto wet soap. The pH is 8. What does this tell you about the soap?

Q 39.5 | Page 81

State whether a solution is acidic, alkaline or neutral if its pH is:
(i) 9
(ii) 4
(iii) 7
(iv) 1
(v) 10
(vi) 3

Q 40 | Page 81

One of the following is a medicine for indigestion. This is:
(a) sodium hydroxide
(b) manganese hydroxide
(c) magnesium hydroxide
(d) potassium hydroxide

Q 41 | Page 81

Bee sting contains:
(a) an acidic liquid
(b) a salt solution
(c) an alkaline liquid
(d) an alcohol

Q 42 | Page 81

Wasp sting contains:
(a) a sugar solution
(b) an acidic liquid
(c) a salt solution
(d) an alkaline liquid

Q 43 | Page 81

One of the following does not inject an acidic liquid into the skin through its sting. This is:
(a) honey bee
(b) ant
(c) wasp
(d) nettle leaf hair

Q 44 | Page 81

A solution turns red litmus blue, its pH is likely to be

• 1

• 4

• 5

• 10

Q 45 | Page 81

A solution turns blue litmus red. Its pH is likely to be:
(a) 7
(b) 5
(c) 8
(d) 14

Q 46 | Page 81

A solution turns phenolphthalein indicator pink. The most likely pH of this solution will be:
(a) 6
(b) 4
(c) 9
(d) 7

Q 47 | Page 81

The colour of methyl orange indicator in a solution is yellow. The pH of this solution is likely to be:
(a) 7
(b) less than 7
(c) 0
(d) more than 7

Q 48 | Page 81

Bee stings can be treated with:
(a) vinegar
(b) sodium hydrogencarbonate
(c) potassium hydroxide
(d) lemon juice

Q 49 | Page 81

Wasp stings can be treated with:
(a) baking soda
(b) vinegar
(c) washing soda
(d) milk of magnesia

Q 50 | Page 81

It has been found that rubbing vinegar on the stung area of the skin of a person gives him relief. The person has been stung by:
(a) wasp
(b) ant
(c) honey bee
(d) nettle leaf hair

Q 51 | Page 81

Fresh milk has a pH of 6. When milk changes into curd, the pH value will:
(a) become 7
(b) become less than 6
(c) become more than 7
(d) remain unchanged

Q 52 | Page 81

The acid produced naturally in our stomach is:
(a) acetic acid
(b) citric acid
(c) hydrochloric acid
(d) sulphuric acid

Q 53 | Page 81

The daffodil plants grow best in a soil having a pH range of 6.0 to 6.5. If the soil in a garden has a pH of 4.5, which substance needs to be added to the soil in order to grow daffodils?
(a) salt
(b) lime
(c) sand
(d) compost

Q 54 | Page 82

A milkman adds a very small amount of baking soda to fresh milk.
(a) Why does he shift the pH of the fresh milk from 6 to slightly alkaline?
(b) Why does this milk take a long time to set as curd?

Q 55 | Page 82

Which of the following elements would from oxides which would indicate pH values less than seven, using moist pH paper?
Magnesium, Carbon, Sulphur, Hydrogen, Copper

Q 56.1 | Page 82

The pH values of five solutions A, B, C, D and E are given below:

 A 1 B 5 C 7 D 11 E 13

Which solution is weakly alkaline.

Q 56.2 | Page 82

The pH values of five solutions A, B, C, D and E are given below:

 A 1 B 5 C 7 D 11 E 13

Which solution isneutral neutral.

Q 56.3 | Page 82

The pH values of five solutions A, B, C, D and E are given below:

 A 1 B 5 C 7 D 11 E 13
Which solution is strongly acidic.
Q 56.4 | Page 82

The pH values of five solutions A, B, C, D and E are given below:

 A 1 B 5 C 7 D 11 E 13
Which solution is  strongly alkaline,
Q 56.5 | Page 82

The pH values of five solutions A, B, C, D and E are given below:

 A 1 B 5 C 7 D 11 E 13
Which solution is weakly acidic?
Q 58 | Page 82

Here are some results of solutions tested with universal indicator paper:

 Sulphuric acid :    Red Metal polish :    Dark blue Washing-up liquid :    Yellow Milk of magnesia :    Light blue Oven cleaner :    Purple Car batter acid :    Pink

Arrange the solutions in order of their increasing pH value (starting with the one with the lowest pH).

Q 59.1 | Page 82

Solution A turns universal indicator blue to purple whereas solution B turns universal indicator orange to red.

What will be the action of solution A on litmus?

Q 59.2 | Page 82

Solution A turns universal indicator blue to purple whereas solution B turns universal indicator orange to red

What will be action of solution B on litmus?

Q 59.3 | Page 82

Solution A turns universal indicator blue to purple whereas solution B turns universal indicator orange to red.

Name any two substances which can give solutions like A.

Q 59.4 | Page 82

Solution A turns universal indicator blue to purple whereas solution B turns universal indicator orange to red.

Name any two substances which can give solutions like B.

Q 59.5 | Page 82

Solution A turns universal indicator blue to purple whereas solution B turns universal indicator orange to red.

What sort of reaction takes place when solution A reacts with solution B?

Q 60.1 | Page 82

A first-aid manual suggests that vinegar should be used to treat wasp stings and baking soda for bee stings. What does this information tell you about the chemical nature of:

wasp stings?

Q 60.2 | Page 82

A first-aid manual suggests that vinegar should be used to treat wasp stings and baking soda for bee stings. What does this information tell you about the chemical nature of:

bee stings?

Q 61 | Page 82

How could the person change his eating habits to lessen chances of suffering from tooth decay?

Q 61.1 | Page 82

Explain why the pH in a person's mouth becomes lower after each meal.

Q 61.2 | Page 82

What damage could be caused while the pH is low?

Q 62 | Page 82

A group of students measured the pH of some substances they found in their homes. Their results are given in the following table:

 Substance pH Substance pH Apples 3.0 Salt 7.0 Baking soda 8.5 Sugar 7.0 Black coffee 5.0 Toothpaste 9.0 Household ammonia 12.0 Vinegar 3.0 Lemon juice 2.5 Washing soda 11.5 Milk 6.5

(a) What would the students have used to measure the pH?
(b) Which solution is the most acidic?
(c) Which solution is the most alkaline?
(d) Which solutions are neutral?
(e) Which solution can be used to treat wasp stings?
(f) Which solutions can be used to treat bee stings?

Q 63.1 | Page 83

Hydrochloric acid reacts with a metal X to form a gas Y which burns with a 'pop' sound. Sodium hydroxide solution also reacts with the same metal X (on heating) to form the same gas Y.

Name X and Y

Q 63.2 | Page 83

Hydrochloric acid reacts with a metal X to form a gas Y which burns with a 'pop' sound. Sodium hydroxide solution also reacts with the same metal X (on heating) to form the same gas Y.

Write the chemical equation of the reaction of metal X with (i) hydrochloric acid, and (ii) sodium hydroxide solution.

### Lakhmir Singh solutions for Class 10 Chemistry (Science) Chapter 2 Acids, Bases and Salts [Pages 96 - 100]

Q 1 | Page 96

What is the chemical formula of baking soda?

Q 1 | Page 96

What is the chemical formula of  washing soda?

Q 2 | Page 96

Write the chemical formula of  soda ash?

Q 2 | Page 96

Write the chemical formula of sodium carbonate decahydrate.

Q 3 | Page 96

State whether the following statement is true or false:
Copper sulphate crystals are always wet due to the presence of water of crystallisation in them.

Q 4 | Page 96

Which of the following salt has a blue colour and why?
CuSO4.5H2O    or    CuSO4

Q 5 | Page 96

What would be the colour of litmus in a solution of sodium carbonate?

Q 6 | Page 96

State the common and chemical names of the compound formed when plaster of Paris is mixed with water.

Q 7 | Page 96

With which substance should chlorine be treated to get bleaching powder?

Q 8 | Page 96

What is the commercial name of calcium sulphate hemihydrate?

Q 9 | Page 97

Name the product formed when Cl2 and H2 produced during the electrolysis of brine are made to combine.

Q 10 | Page 97

Name a calcium compound which hardens on wetting with water.

Q 11 | Page 97

Name a sodium compound which is a constituent of many dry soap powders.

Q 12 | Page 97

Name a metal carbonate which is soluble in water.

Q 13 | Page 97

Name an acid which is present in baking powder.

Q 14 | Page 97

Name the metal whose carbonate is known as washing soda.

Q 15 | Page 97

Which compound is used as an antacid in medicine : NaHCO3 or Na2CO3?

Q 16 | Page 97

What is the common name of (a) NaHCO3 and (b) Na2CO3.10H2O?

Q 17.1 | Page 97

Write the chemical name and formula of common salt.

Q 17.2 | Page 97

Write the chemical name and formula of caustic soda.

Q 18 | Page 97

What are the two main ways in which common salt (sodium chloride) occurs in nature?

Q 19 | Page 97

Name the major salt present in sea-water.

Q 20 | Page 97

How is common salt obtained from sea-water?

Q 21 | Page 97

Why is sodium chloride required in our body?

Q 22 | Page 97

Name three chemicals made from common salt (or sodium chloride).

Q 23 | Page 97

Give any two uses of common salt (sodium chloride).

Q 24 | Page 97

What name is given to the common salt which is mined from underground deposits? How was this salt formed?

Q 25 | Page 97

Name the salt which is used as preservative in pickles, and in curing meat and fish.

Q 26 | Page 97

Name the raw material used for the production of caustic soda.

Q 27 | Page 97

The electrolysis of an aqueous solution of sodium chloride gives us three products. Name them.

Q 28.1 | Page 97

During the electrolysis of a saturated solution of sodium chloride, where is:
chlorine formed?

Q 28.2 | Page 97

During the electrolysis of a saturated solution of sodium chloride, where is:
hydrogen formed?

Q 28.3 | Page 97

During the electrolysis of a saturated solution of sodium chloride, where is:
sodium hydroxide formed?

Q 29.1 | Page 97

Fill in the following blank:

Common salt is obtained from sea-water by the process of.............

Q 29.2 | Page 97

Fill in the following blank:

Rock salt is mined just like ......................

Q 29.3 | Page 97

Fill in the following blank:

Chemical formula of washing soda is ..................

Q 29.4 | Page 97

Fill in the following blank:

Sodium hydrogen carbonate is .................. soda whereas sodium carbonate is ................. soda.

Q 29.5 | Page 97

Fill in the following blank:

The chemical formula of plaster of Paris is ............

Q 30.1 | Page 97

Complete and balance the following chemical equations:

NaCI (aq) + H_2O (l)

Q 30.2 | Page 97

Complete and balance the following chemical equations:

NaHCO_3

Q 30.3 | Page 97

Complete and balance the following chemical equations:

NaCl  + NH_3 + H_2O +CO_2→

Q 30.4 | Page 97

Complete and balance the following chemical equations:

Ca(OH)_2 + Cl_2 ->

Q 31 | Page 97

What is washing soda?

Q 31 | Page 97

State two properties and two uses of washing soda.

Q 32 | Page 97

Write the formulae of sodium chloride and sodium carbonate.

Q 32 | Page 97

Explain why an aqueous solution of sodium chloride is neutral but an aqueous solution of sodium carbonate is basic (or alkaline). Write chemical equations of the reactions involved.

Q 33 | Page 97

Write the chemical formula of ammonium chloride. Explain why an aqueous solution of ammonium chloride is acidic in nature? Illustrate your answer with the help of a chemical equation.

Q 34 | Page 97

What is baking soda?

Q 34 | Page 97

Write the chemical name of baking soda. Give the important uses of baking soda. How does baking soda differ chemically from washing soda?

Q 35 | Page 97

Describe how sodium hydrogencarbonate (baking soda) is produced on a large scale. Write equation of the reaction involved.

Q 36 | Page 97

What happens when a cold and concentrated solution of sodium chloride reacts with ammonia and carbon dioxide? Write the chemical equation of the reaction which takes place.

Q 37.1 | Page 98

What is meant by "water of crystallisation" in a substance? Explain with an example.

Q 37.2 | Page 98

How would you show that blue copper sulphate crystals contain water of crystallisation?

Q 37.3 | Page 98

Explain how anhydrous copper sulphate can be used to detect the presence of moisture (water) in a liquid

Q 38.1 | Page 98

What is the common name of sodium hydrogencarbonate?

Q 38.2 | Page 98

What happens when a solution of sodium hydrogencarbonate is heated? Write equation of the reaction involved.

Q 38.3 | Page 98

Explain why, sodium hydrogencarbonate is used as an antacid.

Q 39.1 | Page 98

What will happen if heating is not controlled while preparing plaster of Paris?

Q 39.2 | Page 98

Write an equation to show the reaction between Plaster of Paris and water

Q 40.1 | Page 98

What happens when copper sulphate crystals are heated strongly? Explain with the help of an equation.

Q 40.2 | Page 98

What happens when a few drops of water are added to anhydrous copper sulphate? Explain with the help of an equation.

Q 41.1 | Page 98

Name two constituents of baking powder.

Q 41.2 | Page 98

How does baking powder differ from baking soda?

Q 41.3 | Page 98

Explain the action of baking powder in the making of cake (or bread). Write equation of the reaction involved.

Q 42.1 | Page 98

What is the chemical name of bleaching powder?

Q 42.2 | Page 98

What is the chemical formula of bleaching powder?

Q 42.3 | Page 98

What are the materials used for the preparation of bleaching powder?

Q 42.4 | Page 98

State one use of bleaching powder (other than bleaching).

Q 43 | Page 98

What does a soda-acid type fire extinguisher contain? How does it work? Explain the working of a soda-acid fire extinguisher with the help of a labelled diagram.

Q 44.1 | Page 98

Name the sodium compound which is used for softening hard water

Q 44.2 | Page 98

Which compound of calcium is used for disinfecting drinking water supply?

Q 44.3 | Page 98

Name a metal compound which has detergent properties (cleansing properties).

Q 44.4 | Page 98

Name one compound of calcium which is used for removing the colour of a coloured cloth.

Q 44.5 | Page 98

Plaster of Paris has a remarkable property of setting  into a hard mass on addition of water.

Q 44.6 | Page 98

Name the substance obtained by the action of chlorine on solid (dry) slaked lime.

Q 45.1 | Page 98

What is gypsum? What happens when gypsum is heated to 100°C (373 K)?

Q 45.2 | Page 98

Name a sodium compound which is used for making borax and glass.

Q 45.3 | Page 98

Name the compound which is used in hospitals for setting fractured bones.

Q 45.4 | Page 98

Which is the real bleaching agent present in bleaching powder?

Q 46.1 | Page 98

What is "baking powder"? How does it make the cake soft and spongy?

Q 46.2 | Page 98

In addition to sodium hydrogencarbonate, baking powders contain a substance X. Name the substance X. What is the role of substance X in the baking powder?

Q 47.1 | Page 98

State two uses each of the following compounds:

Sodium hydroxide

Q 47.2 | Page 98

State two uses each of the following compounds:

Chlorine

Q 47.3 | Page 98

State two uses each of the following compounds:

Hydrogen

Q 47.4 | Page 98

State two uses each of the following compounds:

Hydrochloric acid

Q 48.1 | Page 98

What is the common name of the compound CaOCl2?

Q 48.2 | Page 98

Name the raw material used for the preparation of plaster of Paris.

Q 48.3 | Page 98

Which property of plaster of Paris is utilised in making casts for broken limbs in hospitals?

Q 48.4 | Page 98

Explain why chlorine is used for sterilising drinking water supply.

Q 49.1 | Page 98

What happens when a concentrated solution of sodium chloride (brine) is electrolysed? Write the equation of the reaction involved.

Q 49.2 | Page 98

Why is the electrolysis of a concentrated solution of sodium chloride known as chlor-alkali process?

Q 49.3 | Page 98

Name three products of the chlor-alkali process. State two uses of each of these products.

Q 50.1 | Page 98

Describe how washing soda is produced starting from sodium chloride (common salt). Write equations of all the reactions involved.

Q 50.2 | Page 98

State whether an aqueous solution of washing soda is acidic or alkaline? Give reason for your answer.

Q 50.3 | Page 98

What is meant by saying that washing soda has detergent properties?

Q 50.4 | Page 98

Give two important uses of washing soda

Q 51 | Page 99

What is bleaching powder?

Q 51 | Page 99

How is bleaching powder prepared? Write chemical equation of the reaction involved in the preparation of bleaching powder.

Q 51.2 | Page 99

What happens when bleaching powder reacts with dilute sulphuric acid? Give equation of the reaction involved.

Q 51.3 | Page 99

State two important uses of bleaching powder.

Q 52.1 | Page 99

What is plaster of Paris? Write the chemical formula of plaster of Paris.

Q 52.2 | Page 99

How is plaster of Parish prepared? Write chemical equation of the reaction involved.

Q 52.3 | Page 99

Explain why plaster of Paris should be stored in a moisture-proof container.

Q 52.4 | Page 99

State two important use of plaster of Paris.

Q 53.1 | Page 99

What is a salt?

Q 53.1 | Page 99

Give the names and formulae of any two salts. Also name the acids and bases from which these salt may be obtained.

Q 53.2 | Page 99

What is meant by 'a family of salts'? Explain with examples.

Q 53.3 | Page 99

What is meant by 'hydrated' and 'anhydrous' salts? Explain with examples.

Q 53.4 | Page 99

Write the names, formulae and colours of any two hydrated salts.

Q 53.5 | Page 99

What will be the colour of litmus in an aqueous solution of ammonium chloride salt?

Q 54 | Page 99

The salt which will give an acidic solution on dissolving in water is:
(a) KCl
(b) NH4Cl
(c) Na2Co3
(d) CH3COONa

Q 55 | Page 99

One of the following salts will give an alkaline solution on dissolving in water. This is:

a) Na2CO3
(b) Na2SO4
(c) NaCl
(d) (NH4)2 SO4

Q 56 | Page 99

The salt which will give a neutral solution on dissolving in water will be:
(a) CH3COONa
(b) NH4Cl
(c) KCl
(d) Na2CO3

Q 57 | Page 99

The products of chlor-alkali process are:
(a) NaCl, Cl2 and H2
(b) H2, Cl2 and NaOH
(c) Cl2, Na2CO3 and H2O
(d) NaOH, Cl2 and HCl

Q 58 | Page 99

The number of molecules of water of crystallisation present in washing soda crystals is:
(a) five
(b) two
(c) ten
(d) seven

Q 59 | Page 99

The salt whose aqueous solution will turn blue litmus to red is:
(a) ammonium sulphate
(b) sodium acetate
(c) sodium chloride
(d) potassium carbonate

Q 60 | Page 99

The aqueous solution of one of the following salts will turn red litmus to blue. This salt is:
(a) potassium sulphate
(b) sodium sulphate
(c) sodium chloride
(d) potassium carbonate

Q 61 | Page 99

The salt whose aqueous solution will have no effect on either red litmus or blue litmus is
(a) potassium sulphate
(b) sodium carbonate
(c) ammonium sulphate
(d) sodium acetate

Q 62 | Page 99

The aqueous solution of one of the following salts will turn phenolphthalein indicator pink. This salt is:
(a) KCl
(b) K2SO4
(c) K2CO3
(d) KNO3

Q 63 | Page 99

The formula of baking soda is:
(a) K2CO3
(b) KHCO3
(c) NaHCO3
(d) Na2CO3

Q 64 | Page 99

Which of the following is treated with chlorine to obtain bleaching powder?
(a) CaSO4
(b) Ca(OH)2
(c) Mg(OH)2
(d) KOH

Q 65 | Page 99

Plaster of Paris is prepared by heating one of the following to a temperature of 100°C. This is:
(a) CaSO3.2H2O
(b) CaCl2.2H2O
(c) CaCO3.2H2O
(d) CaSO4.2H2O

Q 66 | Page 99

A salt whose aqueous solution will have a pH of more than 7 will be:
(a) K2CO3
(b) K2SO4
(c) NaCl
(d) NH4Cl

Q 67 | Page 99

A salt is dissolved in water and the pH of this salt solution is measured with a universal indicator paper. If the pH of solution is less than 7, the salt is most likely to be:
(a) CH3COONa
(b) Na2CO3
(c) KCl
(d) NH4Cl

Q 68 | Page 99

Which of the following salts will give an aqueous solution having pH of almost 7?
(a) NH4NO3
(b) NH4Cl
(c) CaCl2
(d) KCl

Q 69.1 | Page 100

P and Q are aqueous solutions of sodium chloride and sodium hydroxide, respectively. Which of these will turn:
(a) blue litmus red?

Q 69.2 | Page 100

P and Q are aqueous solutions of sodium chloride and sodium hydroxide, respectively. Which of these will turn:

red litmus blue?

Q 70 | Page 100

The metal salt A is blue in colour. When salt A is heated strongly over a burner, then a substance B is eliminated and a white powder C is left behind. When a few drops of a liquid D are added to powder C, it becomes blue again. What could be A, B, C and D

Q 71 | Page 100

When the concentrated aqueous solution of substance X is electrolysed, then NaOH, Cl2 and H2 are produced. Name the substance X. What is the special name of this process?

Q 72.1 | Page 100

Consider the following substance:
NaCl, Ca(OH)2, NaHCO3, NH3, Na2CO3, H2O, Cl2, CO2, CaSO4.2H2O, 2CaSO4.H2O, CaOCl2
Which two substance combine to form bleaching powder?

Q 72.2 | Page 100

Consider the following substances:
NaCl, Ca(OH)2, NaHCO3, NH3, Na2CO3, H2O, Cl2, CO2, CaSO4.2H2O, 2CaSO4.H2O, CaOCl2
Which four substances are utilised in the production of washing soda?

Q 72.3 | Page 100

Consider the following substances:
NaCl, Ca(OH)2, NaHCO3, NH3, Na2CO3, H2O, Cl2, CO2, CaSO4.2H2O, 2CaSO4.H2O, CaOCl2

Which compound represents plaster of Paris?

Q 72.4 | Page 100

Consider the following substances:
NaCl, Ca(OH)2, NaHCO3, NH3, Na2CO3, H2O, Cl2, CO2, CaSO4.2H2O, 2CaSO4.H2O, CaOCl2
Which compound is a part of baking powder?

Q 72.5 | Page 100

Consider the following substances:
NaCl, Ca(OH)2, NaHCO3, NH3, Na2CO3, H2O, Cl2, CO2, CaSO4.2H2O, 2CaSO4.H2O, CaOCl2

Which compound is used as an antacid?

Q 73.1 | Page 100

Give one example of a salt which gives an aqueous solution having:

pH less than 7

Q 73.2 | Page 100

Give one example of a salt which gives an aqueous solution having:

pH equal to 7

Q 73.3 | Page 100

Give one example of a salt which gives an aqueous solution having:

pH more than 7

Q 74.1 | Page 100

A compound X which is prepared from gypsum has the property of hardening when mixed with a proper quantity of water.

Identify the compound X

Q 74.2 | Page 100

A compound X which is prepared from gypsum has the property of hardening when mixed with a proper quantity of water.

Write the chemical equation for its preparation

Q 74.3 | Page 100

A compound X which is prepared from gypsum has the property of hardening when mixed with a proper quantity of water.

For what purpose is it used in hospitals?

Q 75.1 | Page 100

Consider the following salts:
Na2CO3, NaCl, NH4Cl, CH3COONa, K2SO4, (NH4)2SO4
Which of salts will give:
acidic solutions?

Q 75.2 | Page 100

Consider the following salts:
Na2CO3, NaCl, NH4Cl, CH3COONa, K2SO4, (NH4)2SO4
Which of salts will give:

neutral solutions?

Q 75.3 | Page 100

Consider the following salts:
Na2CO3, NaCl, NH4Cl, CH3COONa, K2SO4, (NH4)2SO4
Which of these salts will give:

basic solutions (or alkaline solutions)?

Q 76 | Page 100

A white powdery substance having strong smell of chlorine is used for disinfecting drinking water supply at waterworks. Identify the substance. Give its chemical name and write the chemical reaction for its preparation.

Q 77 | Page 100

A salt X when dissolved in distilled water gives a clear solution which turns red litmus blue. Explain the phenomenon.

Q 78 | Page 100

A person found that the cake prepared by him is hard and small in size. Which ingredient has he forgotten to add that would have caused the cake to rise and become light? Explain your answer.

Q 79 | Page 100

A white chemical compound becomes hard on mixing with proper quantity of water. It is also used in surgery to maintain joints in a fixed position. Name the chemical compound.

Q 80 | Page 100

When chlorine and sodium hydroxide being produced during the electrolysis of brine are allowed to mix, a new chemical is formed. Name the chemical and write its uses.

Q 81.1 | Page 100

Write the name and formula of one salt each which contains:

two molecules of water of crystallisation

Q 81.2 | Page 100

Write the name and formula of one salt each which contains:
five molecules of water of crystallisation

Q 81.3 | Page 100

Write the name and formula of one salt each which contains:
ten molecules of water of crystallisation

Q 82.1 | Page 100

How many molecules of water of crystallisation (per formula unit) are present in:
copper sulphate crystals?

Q 82.2 | Page 100

How many molecules of water of crystallisation (per formula unit) are present in:

washing soda?

Q 82.3 | Page 100

How many molecules of water of crystallisation (per formula unit) are present in:

gypsum?

## Lakhmir Singh solutions for Class 10 Chemistry (Science) chapter 2 - Acids, Bases and Salts

Lakhmir Singh solutions for Class 10 Chemistry (Science) chapter 2 (Acids, Bases and Salts) include all questions with solution and detail explanation. This will clear students doubts about any question and improve application skills while preparing for board exams. The detailed, step-by-step solutions will help you understand the concepts better and clear your confusions, if any. Shaalaa.com has the CBSE Class 10 Chemistry (Science) solutions in a manner that help students grasp basic concepts better and faster.

Further, we at Shaalaa.com provide such solutions so that students can prepare for written exams. Lakhmir Singh textbook solutions can be a core help for self-study and acts as a perfect self-help guidance for students.

Concepts covered in Class 10 Chemistry (Science) chapter 2 Acids, Bases and Salts are Introduction to Salt, Chemicals from Common Salt Introduction, Concept of Acids, Bases and Salts, Chemical Properties of Acids and Bases, Importance of Ph in Everyday Life;, pH of Salts, Chemicals from Common Salt - Sodium Hydroxide, Chemicals from Common Salt - Baking Soda, Chemicals from Common Salt - Washing Soda, Chemicals from Common Salt - Bleaching Powder, Chemicals from Common Salt - Plaster of Paris, Crystals of Salts, Acid Or a Base in a Water Solution, Concept of Ph Scale.

Using Lakhmir Singh Class 10 solutions Acids, Bases and Salts exercise by students are an easy way to prepare for the exams, as they involve solutions arranged chapter-wise also page wise. The questions involved in Lakhmir Singh Solutions are important questions that can be asked in the final exam. Maximum students of CBSE Class 10 prefer Lakhmir Singh Textbook Solutions to score more in exam.

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