Question

What is the effect of pressure on the :-

i) Boiling point of water

ii) Freezing point of water

iii) Solubility of gases in water.​

Answer 1

Answer:

1 boiling point of water

Answer 2

i) If the pressure increases, the molecules of water move closer together and a larger amount of energy is required to convert liquid water into steam. So, the boiling point of water increases if pressure increases.

ii) If the pressure increases, immediately the molecules of liquid water are brought much closer together, now, in order to convert to ice, the water has to give out a lesser amount of energy, so the freezing point of water should increase. But, water expands when it freezes, so if the pressure is increased, the freezing point of water decreases instead of increasing.

iii) If the pressure is increased, the solubility of gases in water is increased. This is shown by Henry's Laws. If the pressure increases, then the molecules of water come closer together, the gas molecules are held more tightly in between the water molecules, so the solubility of the gas increases.