Question

que:- what is boiling point? How it is related with:
1. critical temperature
2. Heat Of Vapourisation​

Answer 1

Answer:

Explanation:

The boiling point of a substance is the temperature at which the vapor pressure of a liquid equals the pressure surrounding the liquid[1][2] and the liquid changes into a vapor.

A The critical temperature depends on the strength of the intermolecular interactions that hold a substance together as a liquid. In N2O, a slightly polar substance, weak dipole–dipole interactions and London dispersion forces are important. Butane (C4H10) and pentane (C5H12) are larger, nonpolar molecules that exhibit only London dispersion forces. Methanol, in contrast, should have substantial intermolecular hydrogen bonding interactions. Because hydrogen bonds are stronger than the other intermolecular forces, methanol will have the highest Tc. London forces are more important for pentane than for butane because of its larger size, so n-pentane will have a higher Tc than n-butane. The only remaining question is whether N2O is polar enough to have stronger intermolecular interactions than pentane or butane. Because the electronegativities of O and N are quite similar, the answer is probably no, so N2O should have the lowest Tc.

B We therefore predict the order of increasing critical temperatures as N2O < n-butane < n-pentane < methanol. The actual values are N2O (36.9°C) < n-butane (152.0°C) < n-pentane (196.9°C) < methanol (239.9°C). This is the same order as their normal boiling points—N2O (−88.7°C) < n-butane (−0.2°C) < n-pentane (36.0°C) < methanol (65°C)—because both critical temperature and boiling point depend on the relative strengths of the intermolecular interactions.