Question

Give one example each of electrolytic decomposition and decomposition by sunlight.

Hint:

Silver bromide (\( AgBr \)) also decomposes in sunlight and is used in black and white photography.

Answer 1

Step 1: Understanding the Concept:
Decomposition reactions require energy to break bonds. Based on the source of energy, they are categorized as thermal, electrolytic, or photolytic (sunlight).
Step 2: Detailed Explanation:
1. Electrolytic Decomposition: Decomposition carried out by passing electricity.
Example: Electrolysis of acidified water.
\[ 2H_2O(l) \xrightarrow{\text{Electricity}} 2H_2(g) + O_2(g) \]
2. Decomposition by Sunlight (Photolysis): Decomposition triggered by light energy.
Example: Decomposition of Silver chloride which turns grey in sunlight.
\[ 2AgCl(s) \xrightarrow{\text{Sunlight}} 2Ag(s) + Cl_2(g) \]
Step 3: Final Answer:
Electrolytic decomposition: Electrolysis of water.
Decomposition by sunlight: Decomposition of Silver Chloride (\( AgCl \)).