The water will boil at C) 80°C
Further explanation
Given
Vapour pressure of water = 47 kPa
Required
Boiling point of water
Solution
We can use the Clausius-Clapeyron equation :

Vapour pressure of water at boiling point 100°C=101.325 kPa
ΔH vap for water at 100°C=40657 J/mol
R = 8.314 J/mol K
T₁=boiling point of water at 101.325 kPa = 100+273=373 K
Input given values :
