NCERT solutions Science Textbook for Class 10 chapter 2 Acids, Bases and Salts



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Chapter 2 - Acids, Bases and Salts

Page 18

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

Q 1 | Page 18 | view solution

Page 22

 Why should curd and sour substances not be kept in brass and copper vessels?

Q 1 | Page 22 | view solution

Metal compound A reacts with dilute hydrochloric acid to produce effervescence. The gas evolved extinguishes a burning candle. Write a balanced chemical equation for the reaction if one of the compounds formed is calcium chloride.

Q 3 | Page 22 | view solution

Page 25

 Why do HCl, HNO3, etc., show acidic characters in aqueous solutions while solutions of compounds like alcohol and glucose do not show acidic character?

Q 1 | Page 25 | view solution

 Why does an aqueous solution of an acid conduct electricity?

Q 2 | Page 25 | view solution

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

Q 3 | Page 25 | view solution

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

Q 4 | Page 25 | view solution

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

Q 5 | Page 25 | view solution

How is the concentration of hydroxide ions (OH) affected when excess base is dissolved in a solution of sodium hydroxide?

Q 6 | Page 25 | view solution

Page 28

You have two solutions, A and B. The pH of solution A is 6 and pH of solution B is 8. Which solution has more hydrogen ion concentration? Which of this is acidic and which one is basic?

Q 1 | Page 28 | view solution

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

Q 2 | Page 28 | view solution

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

Q 3 | Page 28 | view solution

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

Q 4 | Page 28 | view solution

Page 33

What is the common name of the compound CaOCl2?

Q 1 | Page 33 | view solution

 Name the substance which on treatment with chlorine yields bleaching powder?

Q 2 | Page 33 | view solution

Name the sodium compound which is used for softening hard water

Q 3 | Page 33 | view solution

What will happen if a solution of sodium hydrocarbonate is heated? Give the equation of the reaction involved.

Q 4 | Page 33 | view solution

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

Q 5 | Page 33 | view solution

Pages 34 - 35

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

(a) 1
(b) 4
(c) 5
(d) 10

Q 1 | Page 34 | view solution

A solution reacts with crushed egg-shells to give a gas that turns lime-water milky. The solution contains

(a) NaCl

(b) HCl

(c) LiCl

(d) KCl

Q 2 | Page 34 | view solution

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) 8mL

(c) 12 mL

(d) 16 mL

Q 3 | Page 34 | view solution

Which one of the following types of medicines is used for treating indigestion?

(a) Antibiotic
(b) Analgesic
(c) Antacid
(d) Antiseptic

Q 4 | Page 34 | view solution

Write word equations and then balanced equations for the reaction taking place when dilute sulphuric acid reacts with zinc granules

Q 5.1 | Page 34 | view solution

Write word equations and then balanced equations for the reaction taking place when − dilute hydrochloric acid reacts with magnesium ribbon.

Q 5.2 | Page 34 | view solution

Write word equations and then balanced equations for the reaction taking place when dilute sulphuric acid reacts with aluminium powder

Q 5.3 | Page 34 | view solution

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

Q 6 | Page 34 | view solution

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

Q 7 | Page 34 | view solution

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

Q 8 | Page 35 | view solution

Five solutions A, B, C, D and E when tested with universal indicator showed pH as 4, 1, 11, 7 and 9, respectively. Which solution is

(a) neutral?
(b) strongly alkaline?
(c) strongly acidic?
(d) weakly acidic?
(e) weakly alkaline?
Arrange the pH in increasing order of hydrogen-ion concentration.

Q 9 | Page 35 | view solution

Equal lengths of magnesium ribbons are taken in test tubes A and B. Hydrochloric acid (HCl) is added to test tube A, while acetic acid (CH3COOH) is added to test tube B. In which test tube will the fizzing occur more vigorously and why?

Q 10 | Page 35 | view solution

Fresh milk from cows have pH of 6. So how does the pH change when this milk is turned to curd?

Q 11 | Page 35 | view solution

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 12 | Page 35 | view solution

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

Q 13 | Page 35 | view solution

 What is a neutralization reaction? Give two examples.

Q 14 | Page 35 | view solution

Give two important uses of washing soda

Q 15.1 | Page 35 | view solution

Give two important uses of  baking soda.

Q 15.2 | Page 35 | view solution

Extra questions

When acids react with metal, which gas is liberated?

view solution

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