Which of the following are exothermic processes?
i. Evaporation of water.
ii. Dilution of an acid (H2SO4).
iii. Reaction of water with quick lime.
iv. Sublimation of camphor (crystals).
- Aiii and iv
- Bii and iii
- Ci and iv
- Di and ii
Show answer and explanation
Correct answer: (b) ii and iii
Explanation
Exothermic processes release heat; dilution of H₂SO₄ and the reaction of water with quick lime (CaO) both give out large amounts of heat.
Quick lime plus water forms slaked lime, Ca(OH)₂, releasing heat, so process iii is exothermic.
Evaporation of water and sublimation of camphor absorb heat, making them endothermic.