[ermac]

Can anyone help me?

Vapor pressure of the mixture of n-hexadecane and n-hexane is 50kPa in temperature 325K. In what temperature first hexadecane crystals will appear?

[Babcock_Hall]

You need to show your attempt first, according to forum rules.

[Enthalpy]

I suppose you have more data? Because melting points can't be deduced from boiling points without a case-by-case measurement. Do you have curves of mp (and maybe bp, less necessary) versus the mixing ratio for instance?

Unless the answer is trivial, like "never because it's pure hexane".