Question

A planet has very low atmospheric pressure compared to Earth. Assuming the surface temperatures on both planets are the same, where will 1.0 L of water boil first?

Answer 1

Well, what do we mean by `"boiling"?`

Explanation:

To be precise, the `"boiling point"` refers to those conditions of temperature AND pressure in which the vapour pressure of the liquid phase is equal to the ambient pressure, and bubbles of vapour form directly in the liquid.

The normal boiling point specifies that the ambient pressure (and thus also the pressure of the boiling liquid) is ONE ATMOSPHERE. It follows that if we REDUCE the ambient pressure, i.e. such as by applying a vacuum, the boiling point of the liquid will REDUCE, given that the ambient pressure is REDUCED, and so the liquid will boil and distil at a LOWER temperature..

And so the boiling point will reduce....and the water will boil faster on the planet with the lower atmospheric pressure....