Give reasons :
Hydrogen is not used in balloons inspite of being the lightest gas.

Explanation

**Step-by-Step Solution:**

1. **Identify the Properties of Hydrogen:**
- Hydrogen is the lightest gas known, which means it has a lower density compared to other gases like air and helium.

2. **Consider the Use of Hydrogen in Balloons:**
- Balloons are typically filled with lighter-than-air gases to make them float. Hydrogen, being lighter than air, seems like a suitable candidate.

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