JAMB Chemistry 1985 Question 15

Question 15

Kinetic Theory and States of Matter

The boiling points of water, ethanol, toluene and butan-2-ol are 373. OK, 351.3K, 383.6 K and 372.5 K respectively. Which liquid has the highest vapour pressure at 323.0 K?

A.Water
B.Toluene
C.Ethanol
D.Butan-2-ol
E.None

Show the answer and explanation

Answer: C (Ethanol)

Explanation

The liquid with the lowest boiling point evaporates most easily, so at any temperature it has the highest vapour pressure. Ethanol boils lowest (351.3 K).