Question

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 1

The correct option is (d) (ii) and (iv)

• Sublimation of dry ice and evaporation of water both are endothermic process and these heat (energy) from their surrounding to get sublime or evaporate.
• Hence, both these processes produce cooling. This is the reason for using dry ice as refrigerant.
• Dilution of sulphuric acid and condensation of water vapours evolve heat. 
• Hence, these are exothermic processes.