Why is granulated zinc and not pure zinc used in the laboratory preparation of dihydrogen?

Explanation

**Step-by-Step Solution:**

1. **Understanding the Properties of Zinc**:
- Pure zinc is a non-porous metal, meaning it does not allow liquids or gases to penetrate through it. This property affects its reactivity with acids.

2. **Reaction with Acids**:
- In the laboratory preparation of dihydrogen (H₂), zinc is typically reacted with dilute acids (like hydrochloric acid, HCl). The reaction is as follows:
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