Ammonia reacts with .......... to give urotropine.

Explanation

To solve the question "Ammonia reacts with .......... to give urotropine," we need to identify the reactant that combines with ammonia to produce urotropine.

### Step-by-Step Solution:

1. **Identify the Reactant**:
We need to find out which compound reacts with ammonia (NH3) to form urotropine.

2. **Recall the Structure of Urotropine**:
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