Question

In which one of the following places the 'boiling point' of water is the highest?
A. Nile Delta
B. Mt. Everest
C. Dead sea
D. Sunderban delta

Answer 1

Hint: A liquid's boiling point changes with applied pressure; the normal boiling point is the temperature at which the vapour pressure equals the typical sea-level air pressure\[\left( {760{\text{ }}mm{\text{ }}\left[ {29.92{\text{ }}inches} \right]{\text{ }}of{\text{ }}mercury} \right)\] . Water boils at \[100^\circ C\left( {212^\circ {\text{ }}F} \right)\] at sea level. The boiling point temperature is lower at greater altitudes.

Complete step by step answer:
Water boils at roughly \[{100^ \circ }C\] at standard atmospheric pressure\[\left( {1{\text{ }}atmosphere{\text{ }} = {\text{ }}0.101325{\text{ }}MPa} \right)\] . That simply means that the vapour pressure of water at that temperature is one atmosphere. Because the temperature must be greater at higher pressures (such as the pressure generated in a pressure cooker) before the vapour pressure reaches the ambient pressure, water under pressure boils at a higher temperature. Similarly, when the surrounding pressure is low (as at high elevations), the vapour pressure arrives at that pressure at a lower temperature.
The Dead Sea surface is so low that water boils at around \[{101^ \circ }C\] . Because of the high salt concentration, Dead Sea water boils at \[{105^ \circ }C\] under atmospheric pressure.
Hence, the correct option is: (C) Dead sea.

Note: The vapour pressure curve denotes the relationship between vapour pressure and temperature (or, in the opposite direction, boiling temperature and pressure). The vapour pressure curve of water is extremely important because it governs the relationship between temperature and pressure in any process in which water transitions from a liquid to a vapour state or vice versa.