Why does magnesium ribbon start floating in hot water?

Explanation

To understand why magnesium ribbon starts floating in hot water, let's break down the process step by step.

### Step-by-Step Solution:

1. **Reaction with Water**: When magnesium ribbon is placed in hot water, it reacts with the water (H2O). The reaction can be represented by the chemical equation:
\[ \text{Mg} + 2\text{H}_2\text{O} \rightarrow \text{Mg(OH)}_2 + \text{H}_2 \]
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