Question

Which of the following are exothermic process?
1. Respiration
2. Burning of coal
3. Dilution of an acid
4. Evaporation of water

• A. Only 4
• B. 1 and 4
• C. 2, 3, and 4
• D. 1, 2, and 3

Answer 1

The correct option is D 1, 2, and 3

1. The process of respiration is considered an exothermic process because energy is released in the process which is used by the body for various life process and activities.

$C_6{H}_{12}{O}_6\left(\mathrm{aq}\right)+6O_2\left(\mathrm{aq}\right)\to 6{\mathrm{CO}}_2\left(\mathrm{aq}\right)+6H_{2}O\left(l\right)+\mathrm{energy}$

2. During the burning of coal carbon dioxide gas is releases with the emission of heat energy. So, this is also an exothermic process.
3. Dilution of acid is also an exothermic reaction because heat is released during this process.
4. Evaporation is an endothermic process because water molecules absorb heat from the surrounding inorder to vapourise.

Hence 1, 2, and 3 are an exothermic reaction.