Question

A closed bottle containing water at ${30}^{o}C$ is carried to the moon in spaceship. If it is placed on the surface of the moon, what will happen to the water as soon as the lid is opened?

• A. The water will freeze.
• B. The water will boil.
• C. It will decompose into $H_2$ and $O_2$.
• D. Nothing will happen to it.

Answer 1

Answer: (B)

The water will boil.

Any liquid will start to boil if the vapour pressure of the liquid is greater than the external pressure.Since the pressure in vacuum is zero,any liquid will instantaneously boil when left open.
Water at ${30}^0$C will have some vapour pressure, hence will boil.