Chapter 1 · Chemical Reactions and Equations

NCERT Exemplar Class 10 Science Chapter 1 Multiple Choice Questions

All 18 questions of NCERT Exemplar Class 10 Science Chapter 1 Multiple Choice Questions (Chemical Reactions and Equations), in the book's order, each with its answer and a step-by-step solution.

1. Q1
   Which of ​the following ​is not ​a ​physical change?

   1. (a)Boiling of water to give water vapour
   2. (b)Melting of ice to give water
   3. (c)Dissolution of salt in water
   4. (d)Combustion of Liquefied Petroleum Gas (LPG)
   Show answer

   (d) Combustion of Liquefied Petroleum Gas (LPG)

   Step-by-step solution →
2. Q2
   The following reaction ​is an example of a $$4{\text{NH}}_3(g)+5{\text{O}}_2(g)\to 4\text{NO}(g)+6{\text{H}}_2\text{O}(g)$$

   1. (i)displacement reaction
   2. (ii)combination reaction
   3. (iii)redox reaction
   4. (iv)​neutralisation ​reaction

   1. (a)(i) and (iv)
   2. (b)(ii) and (iii)
   3. (c)(i) and (iii)
   4. (d)(iii) and (iv)
   Show answer

   (c) (i) and (iii)

   Step-by-step solution →
3. Q3
   Which of the following statements about the ​given reaction are correct? $$3\text{Fe}(s)+4{\text{H}}_2\text{O}(g)\to {\text{Fe}}_3{\text{O}}_4(s)+4{\text{H}}_2(g)$$

   1. (i)Iron metal is getting oxidised
   2. (ii)​Water is getting reduced
   3. (iii)Water is ​acting as reducing agent
   4. (iv)​Water is acting ​as oxidising ​agent

   1. (a)(i), (ii) and (iii)
   2. (b)(iii) and (iv)
   3. (c)(i), (ii) and (iv)
   4. (d)(ii) and (iv)
   Show answer

   (c) (i), (ii) and (iv)

   Step-by-step solution →
4. Q4
   Which of the following ​are exothermic ​processes?

   1. (i)Reaction of water ​with quick lime
   2. (ii)Dilution ​of ​an ​acid
   3. (iii)Evaporation of ​water
   4. (iv)Sublimation of camphor (crystals)

   1. (a)(i) and (ii)
   2. (b)(ii) and (iii)
   3. (c)(i) and (iv)
   4. (d)(iii) and (iv)
   Show answer

   (a) (i) and (ii)

   Step-by-step solution →
5. Q5
   Three beakers labelled as A, B and C each containing 25 mL of water were taken. A small ​amount of NaOH, anhydrous ${\text{CuSO}}_4$ and NaCl were added to the beakers A, B and C respectively. It was observed that there was an increase in the temperature of the solutions contained in beakers A and B, ​whereas in case of beaker C, ​the temperature of the solution falls. Which one of the ​following statement(s) is(are) correct?

   1. (i)In beakers A and B, exothermic process has occurred.
   2. (ii)In beakers A and B, ​endothermic process has occurred.
   3. (iii)In beaker C exothermic process ​has occurred.
   4. (iv)In ​beaker C endothermic process has occurred.

   1. (a)(i) only
   2. (b)(ii) only
   3. (c)(i) and (iv)
   4. (d)(ii) and (iii)
   Show answer

   (c) (i) and (iv)

   Step-by-step solution →
6. Q6
   A dilute ferrous sulphate solution ​was gradually added ​to the ​beaker containing acidified permanganate solution. The light purple colour of the solution ​fades and finally disappears. Which of the following ​is the correct explanation for ​the observation?

   1. (a)${\text{KMnO}}_4$ is an oxidising agent, it oxidises ${\text{FeSO}}_4$
   2. (b)${\text{FeSO}}_4$ acts as an oxidising agent and oxidises ${\text{KMnO}}_4$
   3. (c)The colour disappears due to dilution; no reaction is involved
   4. (d)${\text{KMnO}}_4$ is an unstable compound and decomposes in presence of ${\text{FeSO}}_4$ to a colourless compound.
   Show answer

   (a) ${\text{KMnO}}_4$ is an oxidising agent, it oxidises ${\text{FeSO}}_4$

   Step-by-step solution →
7. Q7
   Which ​among the ​following is(are) ​double ​displacement ​reaction(s)?

   1. (i)$\text{Pb}+{\text{CuCl}}_2\to {\text{PbCl}}_2+\text{Cu}$
   2. (ii)${\text{Na}}_2{\text{SO}}_4+{\text{BaCl}}_2\to {\text{BaSO}}_4+2\text{NaCl}$
   3. (iii)$\text{C}+{\text{O}}_2\to {\text{CO}}_2$
   4. (iv)${\text{CH}}_4+2{\text{O}}_2\to {\text{CO}}_2+2{\text{H}}_2\text{O}$

   1. (a)(i) and (iv)
   2. (b)(ii) only
   3. (c)(i) and (ii)
   4. (d)(iii) and (iv)
   Show answer

   (b) (ii) only

   Step-by-step solution →
8. Q8
   Which among the following statement(s) is(are) true? Exposure ​of silver chloride to sunlight for a long duration ​turns grey due ​to

   1. (i)the ​formation of silver by decomposition of silver chloride
   2. (ii)sublimation of ​silver chloride
   3. (iii)decomposition of ​chlorine gas from silver chloride
   4. (iv)oxidation ​of silver ​chloride

   1. (a)(i) only
   2. (b)(i) and (iii)
   3. (c)(ii) and (iii)
   4. (d)(iv) only
   Show answer

   (a) (i) only

   Step-by-step solution →
9. Q9
   Solid ​calcium oxide reacts vigorously with water to form calcium hydroxide accompanied by liberation of heat. This ​process is called slaking of lime. Calcium hydroxide dissolves in water to form its solution ​called lime water. Which among the following is (are) true about slaking of lime and the solution formed?

   1. (i)It ​is an endothermic reaction
   2. (ii)It is an exothermic reaction
   3. (iii)The pH of the resulting solution will be more than ​seven
   4. (iv)The pH of the resulting solution will be ​less ​than seven

   1. (a)(i) and (ii)
   2. (b)(ii) and (iii)
   3. (c)(i) and (iv)
   4. (d)(iii) and (iv)
   Show answer

   (b) (ii) and (iii)

   Step-by-step solution →
10. Q10
    Barium ​chloride on ​reacting with ammonium sulphate forms barium sulphate and ammonium chloride. Which of the following correctly represents the type of ​the ​reaction involved?

    1. (i)​Displacement reaction
    2. (ii)Precipitation ​reaction
    3. (iii)Combination ​reaction
    4. (iv)Double displacement reaction

    1. (a)(i) only
    2. (b)(ii) only
    3. (c)(iv) only
    4. (d)(ii) and (iv)
    Show answer

    (d) (ii) and (iv)

    Step-by-step solution →
11. Q11
    Electrolysis of ​water is ​a decomposition ​reaction. The ​mole ratio of hydrogen and oxygen gases liberated ​during electrolysis ​of water is

    1. (a)$1:1$
    2. (b)$2:1$
    3. (c)$4:1$
    4. (d)$1:2$
    Show answer

    (b) $2:1$

    Step-by-step solution →
12. Q12
    Which of ​the following is(are) ​an endothermic process(es)?

    1. (i)Dilution of sulphuric ​acid
    2. (ii)​Sublimation of ​dry ice
    3. (iii)Condensation of water vapours
    4. (iv)​Evaporation of ​water

    1. (a)(i) and (iii)
    2. (b)(ii) only
    3. (c)(iii) only
    4. (d)(ii) and (iv)
    Show answer

    (d) (ii) and (iv)

    Step-by-step solution →
13. Q13
    In the double displacement ​reaction between aqueous potassium iodide and aqueous lead nitrate, a yellow precipitate of ​lead iodide is formed. While performing the activity if lead ​nitrate is not available, ​which ​of the ​following ​can be used in place of lead nitrate?

    1. (a)Lead sulphate (insoluble)
    2. (b)Lead acetate
    3. (c)Ammonium nitrate
    4. (d)Potassium sulphate
    Show answer

    (b) Lead acetate

    Step-by-step solution →
14. Q14
    Which of the ​following gases ​can be used ​for ​storage of fresh sample ​of an oil for ​a long ​time?

    1. (a)Carbon dioxide or oxygen
    2. (b)Nitrogen or oxygen
    3. (c)Carbon dioxide or helium
    4. (d)Helium or nitrogen
    Show answer

    (d) Helium or nitrogen

    Step-by-step solution →
15. Q15
    The following reaction is used ​for the preparation ​of oxygen gas ​in the laboratory $$2{\text{KClO}}_3(s)\underset{\text{Catalyst}}{\overset{\text{Heat}}{\to }}2\text{KCl}(s)+3{\text{O}}_2(g)$$ Which of the following ​statement(s) is(are) correct about ​the ​reaction?

    1. (a)It is a decomposition reaction and endothermic in nature
    2. (b)It is a combination reaction
    3. (c)It is a decomposition reaction and accompanied by release of heat
    4. (d)It is a photochemical decomposition reaction and exothermic in nature
    Show answer

    (a) It is a decomposition reaction and endothermic in nature

    Step-by-step solution →
16. Q16
    Which ​one ​of the ​following ​processes ​involve chemical reactions?

    1. (a)Storing of oxygen gas under pressure in a gas cylinder
    2. (b)Liquefaction of air
    3. (c)Keeping petrol in a china dish in the open
    4. (d)Heating copper wire in presence of air at high temperature
    Show answer

    (d) Heating copper wire in presence of air at high temperature

    Step-by-step solution →
17. Q17
    In ​which of the ​following chemical ​equations, ​the abbreviations represent the correct ​states of the reactants ​and ​products involved at reaction temperature?

    1. (a)$2{\text{H}}_2(l)+{\text{O}}_2(l)\to 2{\text{H}}_2\text{O}(g)$
    2. (b)$2{\text{H}}_2(g)+{\text{O}}_2(l)\to 2{\text{H}}_2\text{O}(l)$
    3. (c)$2{\text{H}}_2(g)+{\text{O}}_2(g)\to 2{\text{H}}_2\text{O}(l)$
    4. (d)$2{\text{H}}_2(g)+{\text{O}}_2(g)\to 2{\text{H}}_2\text{O}(g)$
    Show answer

    (d) $2{\text{H}}_2(g)+{\text{O}}_2(g)\to 2{\text{H}}_2\text{O}(g)$

    Step-by-step solution →
18. Q18
    Which ​of the ​following are ​combination reactions?

    1. (i)$2{\text{KClO}}_3\stackrel{\text{Heat}}{\to }2\text{KCl}+3{\text{O}}_2$
    2. (ii)$\text{MgO}+{\text{H}}_2\text{O}\to {\text{Mg(OH)}}_2$
    3. (iii)$4\text{Al}+3{\text{O}}_2\to 2{\text{Al}}_2{\text{O}}_3$
    4. (iv)$\text{Zn}+{\text{FeSO}}_4\to {\text{ZnSO}}_4+\text{Fe}$

    1. (a)(i) and (iii)
    2. (b)(iii) and (iv)
    3. (c)(ii) and (iv)
    4. (d)(ii) and (iii)
    Show answer

    (d) (ii) and (iii)

    Step-by-step solution →