Acids, Bases and Salts - NCERT Exemplar

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Multiple Choice Questions : -

Q.1 What happens when a solution of an acid is mixed with a solution of a base in a test tube?

(i) The temperature of the solution increases.

(ii) The temperature of the solution decreases.

(iii) The temperature of the solution remains the same.

(iv)  Salt formation takes place

(a) (I) only (b) (I) and (III)

(c) (II) and (iii) (d) (I) and (IV)

Sol.  (d)

Q.2 An aqueous solution turns red litmus solution blue. Excess addition of which of the following solution would reverse the change?

(a) Baking powder

(b) Lime

(c) Ammonium hydroxide solution

(d) Hydrochloric acid

Sol.   (d)

Q.3 During the preparation of hydrogen chloride gas on a humid day, the gas is usually passed through the guard tube containing calcium chloride. The role of calcium chloride taken in the guard tube is to

(a) Absorb the evolved gas

(b) Moisten the gas

(c) Absorb moisture from the gas

(d) Absorb Cl ions from the evolved gas

Sol.   (c)

Q.4 Which of the following salts does not contain water of crystallisation?

(a) Blue vitriol

(b) Baking soda

(c) Washing soda

(d) Gypsum

Sol.  (b)

Q.5 Sodium carbonate is a basic salt because it is a salt of

(a) Strong acid and strong base

(b) Weak acid and weak base

(c) Strong acid and weak base

(d) Weak acid and strong base

Sol.   (d)

Q.6 Calcium phosphate is present in tooth enamel. Its nature is

(a) basic

(b) acidic

(c) neutral

(d) Amphoteric

Sol.  (c)

Q.7 A sample of soil is mixed with water and allowed to settle. The clear supernatant solution turns the pH paper yellowish-orange. Which of the following would change the colour of this pH paper to greenish-blue?

(a) Lemon juice

(b) Vinegar

(c) Common salt

(d) An antacid

Sol.  (d)

Q.8 Which of the following gives the correct increasing order of acidic strength?

(a) Water < Acetic acid < Hydrochloric acid

(b) Water < Hydrochloric acid < Acetic acid

(c) Acetic acid < Water < Hydrochloric acid

(d) Hydrochloric acid < Water < Acetic acid

Sol.  (a)

Q.9 If a few drops of a concentrated acid accidentally spills over the hand of a student, what should be done?

(a) Wash the hand with saline solution

(b) Wash the hand immediately with plenty of water and apply a paste of sodium hydrogen carbonate

(c) After washing with plenty of water, apply solution of sodium hydroxide on the hand

(d) Neutralise the acid with a strong alkali

Sol. (b)

Q.10 Sodium hydrogen carbonate when added to acetic acid evolves a gas. Which of the following statements are true about the gas evolved?

(i) It turns lime water milky

(ii) It extinguishes a burning splinter

(iii) It dissolves in a solution of sodium hydroxide

(iv) It has a pungent odour

(a) (i) and (ii)

(b) (i), (ii) and (iii)

(c) (ii), (iii) and (iv)

(d) (i) and (iv)

Sol. (a)

Q.11 Common salt besides being used in kitchen can also be used as the raw material for making

(i) Soda

(ii) Bleaching powder

(iii) Baking soda

(iv) Slaked lime

(a) (i) and (ii)

(b) (i), (ii) and (iv)

(c) (i) and (iii)

(d) (i), (iii) and (iv)

Sol.  (c)

Q.12 One of the constituents of baking powder is sodium hydrogen carbonate, the other constituent is

(a) Hydrochloric acid

(b) Tartaric acid

(c) Acetic acid

(d) Sulphuric acid

Sol. (b)

Q.13 To protect tooth decay we are advised to brush our teeth regularly. The nature of the tooth paste commonly used is

(a) Acidic

(b) Neutral

(c) Basic

(d) Corrosive

Sol. (c)

Q.14 Which of the following statements is correct about an aqueous solution of an acid and of a base?

(i) Higher the pH, stronger the acid

(ii) Higher the pH, weaker the acid

(iii) Lower the pH, stronger the base

(iv) Lower the pH, weaker the base

(a) (i) and (iii)

(b) (ii) and (iii)

(c) (i) and (iv)

(d) (ii) and (iv)

Sol.  (c)

Q.15 The pH of the gastric juices released during digestion is

(a) Less than 7

(b) More than 7

(c) Equal to 7

(d) Equal to 0

Sol.  (?)

Q.16  Which of the following phenomena occur, when a small amount of acid is added to water?

(i) Ionisation

(ii) Neutralisation

(iii) Dilution

(iv) Salt formation

(a) (i) and (ii)

(b) (i) and (iii)

(c) (ii) and (iii)

(d) (ii) and (iv)

Sol.  (b) 

Q.17 Which one of the following can be used as an acid–base indicator by a visually impaired student?

(a) Litmus

(b) Turmeric

(c) Vanilla essence

(d) Petunia leaves

Sol. (c) 

Q.18 Which of the following substance will not give carbon dioxide on treatment with dilute acid?

(a) Marble

(b) Limestone

(c) Baking soda

(d) Lime

Sol. (d) 

Q.19 Which of the following is acidic in nature?

(a) Lime juice

(b) Human blood

(c) Lime water

(d) Antacid

Sol. (b) 

Q.20 In an attempt to demonstrate electrical conductivity through an electrolyte, the following apparatus (Given Figure Below) was set up.

Which among the following statement(s) is (are) correct?

(i) Bulb will not glow because electrolyte is not acidic

(ii) Bulb will glow because NaOH is a strong base and furnishes ions for conduction.

(iii) Bulb will not glow because circuit is incomplete

(iv) Bulb will not glow because it depends upon the type of electrolytic solution

(a) (i) and (iii)

(b) (ii) and (iv)

(c) (ii) only

(c) (iv) only

Sol.  (c)

Q.21 Which of the following is used for dissolution of gold?

(a) Hydrochloric acid

(b) Sulphuric acid

(c) Nitric acid

(d) Aqua regia

Sol. (d)

Q.22 Which of the following is not a mineral acid?

(a) Hydrochloric acid

(b) Citric acid

(c) Sulphuric acid

(d) Nitric acid

Sol.  (b)

Q.23 Which among the following is not a base?

(a) NaOH

(b) KOH

(c) NH4OH

(d) C2H5 OH

Sol. (d)

Q.24 Which of the following statements is not correct?

(a) All metal carbonates react with acid to give a salt, water and carbon dioxide

(b) All metal oxides react with water to give salt and acid

(c) Some metals react with acids to give salt and hydrogen

(d) Some non metal oxides react with water to form an acid

Sol.  (b) 

Q.25 Match the chemical substances given in Column (A) with their appropriate application given in

(a) A—(ii), B—(i), C—(iv), D—(iii)

(b) A—(iii), B—(ii), C—(iv), D—(i)

(c) A—(iii), B—(iv), C—(i), D—(ii)

(d) A—(ii), B—(iv), C—(i), D—(iii)

Sol.  (c)

Q.26 Equal volumes of hydrochloric acid and sodium hydroxide solutions of same concentration are mixed and the pH of the resulting solution is checked with a pH paper. What would be the colour obtained? (You may use colour guide given in given Figure

(a) Red

(b) Yellow

(c) Yellowish green

(d) Blue

Sol. (c)

Q.27 Which of the following is (are) true when HCl (g) is passed through water?

(i) It does not ionise in the solution as it is a covalent compound.

(ii) It ionises in the solution

(iii) It gives both hydrogen and hydroxyl ion in the solution

(iv) It forms hydronium ion in the solution due to the combination of hydrogen ion with water molecule

(a) (i) only

(b) (iii) only

(c) (ii) and (iv)

(d) (iii) and (iv)

Sol.  (c)

Q.28 Which of the following statements is true for acids?

(a) Bitter and change red litmus to blue

(b) Sour and change red litmus to blue

(c) Sour and change blue litmus to red

(d) Bitter and change blue litmus to red

Sol. (c)

Q.29 Which of the following are present in a dilute aqueous solution of hydrochloric acid?

(a) H3O+ + Cl

(b) H3O+ + OH

(c) Cl + OH

(d) Unionised HCl

Sol.  (a)

Q.30 Identify the correct representation of reaction occurring during “chlor-alkali” process

(a) 2NaCl (l) + 2H2O (l) → 2NaOH (l) + Cl2 (g) + H2 (g)

(b) 2NaCl (aq) + 2H2O (aq) → 2NaOH (aq) + Cl2 (g) + H2 (g)

(c) 2NaCl (aq) + 2H2O (l) → 2NaOH (aq) + Cl2 (aq) + H2 (aq)

(d) 2NaCl (aq) + 2H2O (l) → 2NaOH (aq) + Cl2 (g) + H2 (g)

Sol. (d)

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