Question

3. (a) Give an example for a combination reaction which is exothermic.
(b) Identify the oxidising agent, reducing agent in the following reaction.
H2S + Cl2
2HCl + S
(c) Name the phenomenon due to which the taste and smell of oily food change when
kept for a long time in open. Suggest one method to prevent it.
​

Answer 1

Explanation:

3(a).Cao + H2O = Can(OH)2 + Heat

It is a combination reaction because two compounds on reaction give one product.

As heat is also evolved during the process, thus it is also an example of exothermic reaction.

(b). H2s + Cl2= 2HCL + S

Oxidising agent - Cl2

Reducing agent - H2S

(c) This is known as rancidity. Prevention Oily food must be kept in airtight containers.