Which among the following changes are exothermic or endothermic in nature?
(a) Decomposition of ferrous sulphate
(b) Dilution of sulphuric acid
`(c)`Dissolution of sodium hydroxide in water
(d) Dissolution of ammonium chloride in water

Explanation

To determine whether the given changes are exothermic or endothermic, we need to analyze each process based on the heat exchange involved.

### Step-by-Step Solution:

1. **Decomposition of Ferrous Sulphate**:
- **Analysis**: Decomposition reactions typically require heat to break down compounds into simpler substances. In this case, ferrous sulphate (FeSO₄) decomposes when heated.
- **Conclusion**: This process is **endothermic** because it absorbs heat from the surroundings.

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