Question

Among (A) water (B) Ethanol and (C) Mercury, the correct order of the vapour pressure at room temperature is:

• A. A > B > C
• B. B > A > C
• C. C > B > A
• D. B > C > A

Answer 1

The correct option is B B > A > C

Vapor pressure is the pressure caused by the evaporation of liquids. Three common factors that influence vapor pressure are surface area, intermolecular forces and temperature. The vapor pressure of a molecule differs at different temperatures.

Strong intermolecular forces produce a lower rate of evaporation and a lower vapor pressure. Weak intermolecular forces produce a higher rate of evaporation and a higher vapor pressure. Mercury has strong intermolecular force than water and ethanol and ethanol is more volatile than water and mercury.

Thus, Answer is $B>A>C$