Multiple choice

Which gas is preferred over hydrogen in hot air balloons?

  1. Helium

  2. Argon

  3. Neon

  4. Krypton

  5. Xenon

Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Helium is preferred over hydrogen in hot air balloons because hydrogen can readily catch fire and helium is lighter than any of the other rare gases.