Multiple choice general knowledge

When a liquid boils, the Vapour Pressure is ........Atmospheric Pressure?

  1. more

  2. equal to

  3. less

  4. none of above
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

When a liquid boils, its vapor pressure becomes equal to the atmospheric pressure. At this point, bubbles can form throughout the liquid and rise to the surface because the pressure exerted by the vapor molecules is sufficient to overcome the external atmospheric pressure. Below the boiling point, vapor pressure is less than atmospheric pressure, and bubbles cannot form. Above the boiling point (superheating), vapor pressure would exceed atmospheric pressure, but this is not the normal boiling condition.

Keep practicing — related questions