Question 12 - MCQs from NCERT Exemplar - Chapter 1 Class 10 - Chemical Reactions and Equations

Which of the following is(are) an endothermic process(es)?

(i) Dilution of sulphuric acid

(ii) Sublimation of dry ice

(iii) Condensation of water vapours

(iv) Evaporation of water

(A) (i) and (iii) 

(B) (ii) only

(C) (iii) only 

(D) (ii) and (iv)

Answer

Here,

• Endo means in and thermic means heat . So, in these reactions heat is absorbed.
• Exo means out and thermic means heat . So, in these reactions, heat is evolved

Here,

• Dilution of sulphuric acid generates heat, so it is an exo thermic process
• Sublimation of dry ice needs heat, so it is an endo thermic process
• Condensation of water vapours generates heat, so it is an exo thermic process
• Evaporation of water needs heat, so it is an endo thermic process

So, the correct answer is (d) -  (ii) and (iv)