Multiple choice

Which gas is filled in balloons?

  1. Hydrogen

  2. Carbon dioxide

  3. Oxygen

  4. Sulphur
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Hydrogen is the lightest gas and was historically used in balloons because it provides excellent lift. However, helium is now preferred for safety reasons since hydrogen is highly flammable (as seen in the Hindenburg disaster). The question reflects older practice but the answer is historically accurate.

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