Question

Water boils at a temperature less than ${{100}^{o}}C$ on the top of a high mountain.
A. True
B. False

Answer 1

Hint: Boiling of water will depend on the atmospheric pressure, so by understanding the amount of atmospheric pressure present at the top of high mountain, we can comment if the water will boil or not, as the vapor pressure and atmospheric pressure are two important terms while considering if the water boils or not at high altitudes.

Complete solution:
We know that a liquid begins to boil when vapor pressure equals atmospheric pressure at specific temperature during that moment.
At elevated altitudes, like mountains, which are considerably higher than sea-level, the boiling point of water is lower due to the decreased atmospheric pressure, which compensates for the lower temperature that is required for cooking that involves boiling or steaming.
Hence, water will boil at temperature below ${{100}^{o}}C$ on the top of a high mountain because of the decreased atmospheric pressure on the mountains.

Therefore, the correct answer is Option (A).

Additional Information:
A pressure cooker is often used to compensate for the low atmospheric pressure at very high elevations. Under these circumstances, water boils at temperatures significantly below ${{100}^{o}}C$ and, without the use of a pressure cooker, may leave boiled foods undercooked.

Note:
At high altitudes, pressure acts differently and understanding the behavior of pressure at different altitudes will help to understand the temperature which is required for water to boil. So, to get the answer for this question, it is necessary to understand the relation between the vapor pressure and atmospheric pressure, which will help to get the temperature required for water to boil.