Question

Choose the substance with the lowest vapor pressure at a given temperature.

		CO2
		CaI2
		BF3
		Ar
		PF5

Answer 1

Vapor pressure is the pressure exerted by the vapor of that liquid at equilibrium.

The liquid which has lowest intermolecular forces that has higher vapor pressure.

So to answer this question we need to determine the liquid with lowest intermolecular forces.

In the given molecules CaI2 is ionic and so its intermolecular force will be highest in all. Rest of all are covalent in nature. Covalent molecule has less intermolecular forces than ionic.

So the answer for this question is CaI2