Boiling point at a certain pressure

[kthouz]

How can one calculate the boiling of a liquid at a pressure different from standard temperature?

Am trying to do it using the ideal gas equation,

(PV)/T=(P'V')/T'
Where P is the STP, V is 22.4l, T= boiling point at STP, P'= new pressure, V' is the new volume and T' is to be found. But is it easy to find V'.

But I found another equation of Clausius-Clapeyton which involves the heat of vaporisation. Using this equation, the problem is finding the heat of vaporisation. Can anyone help me?

 

[Chestermiller]

The ideal gas law is the wrong equation to use (since it has nothing to do with vapor-liquid equilibrium) but the Clausius-Clapeyron equation is the correct equation to use (since it is derived by specifically focusing on vapor-liquid equilibrium thermodynamics).