Classify the following processes as exothermic or endothermic:
(A) Burning of a match stick (B) Melting of ice
(C ) Molten metal solidifies (D) Reaction between `Na` and `H_(2)O`
(E ) Rubbing alcohol evaporates.

Answer

To classify the given processes as exothermic or endothermic, we will analyze each process based on whether it releases heat (exothermic) or absorbs heat (endothermic).

### Step-by-Step Solution:

1. **Burning of a match stick (A)**:
- When a match stick is burned, it undergoes combustion, which releases a significant amount of heat and light.
- **Classification**: Exothermic

2. **Melting of ice (B)**:
- Ice absorbs heat from the surroundings to change its state from solid to liquid. This process requires energy input to overcome the forces holding the ice molecules together.
- **Classification**: Endothermic

3. **Molten metal solidifies (C)**:
- When molten metal solidifies, it releases heat to the surroundings as it transitions from a liquid state to a solid state. The temperature of the metal decreases as it loses heat.
- **Classification**: Exothermic

4. **Reaction between Na and H₂O (D)**:
- Sodium reacts vigorously with water, producing sodium hydroxide and hydrogen gas, along with a large release of heat. This reaction is highly exothermic.
- **Classification**: Exothermic

5. **Rubbing alcohol evaporates (E)**:
- When rubbing alcohol evaporates, it absorbs heat from the skin or the surrounding environment, resulting in a cooling effect. This process requires energy to convert the liquid into vapor.
- **Classification**: Endothermic

### Final Classifications:
- (A) Burning of a match stick: **Exothermic**
- (B) Melting of ice: **Endothermic**
- (C) Molten metal solidifies: **Exothermic**
- (D) Reaction between Na and H₂O: **Exothermic**
- (E) Rubbing alcohol evaporates: **Endothermic**