What is the approximate vapor pressure when the liquid water boils at about 50°c?

a. o 230 mmhg

b. 5 mmhg

c. o 760 mmhg

d. o 380 mmhg

The vapor pressure of the water when it boils at 50°C is 99.91 mmHg

Explanation:

To calculate the final pressure, we use the Clausius-Clayperon equation, which is:

where,

= initial pressure which is the pressure at normal boiling point = 760 mmHg

= final pressure = ?

= Enthalpy of vaporization = 40.65 kJ/mol = 40650 J/mol     (Conversion factor: 1 kJ = 1000 J)

R = Gas constant = 8.314 J/mol K

= initial temperature =

= final temperature =

Putting values in above equation, we get:

Hence, the vapor pressure of the water when it boils at 50°C is 99.91 mmHg