CBSE Class 12 · 2005 · All India · SolutionsShort Answer

State Henry's law for solubility of a gas in a liquid. Explain the significance of Henry's law constant (K

_{H}

). At the same temperature, hydrogen is more soluble in water than helium. Which of them will have a higher value of K

_{H}

and why?

Answer: p = K_H x; the higher the K_H, the lower the solubility. Helium, being less soluble, has the higher K_H.

Solution

Henry's law: at constant temperature, the solubility of a gas in a liquid is directly proportional to the pressure of the gas above the liquid,

p = K_{H} x

Significance of

K_{H}

: for a given pressure,

x = p / K_{H}

— so the larger the value of

K_{H}

, the lower the solubility of the gas at that temperature.
Since hydrogen is more soluble than helium at the same temperature, helium has the smaller

x

for the same

p

, i.e.

helium has the higher K_{H}

CBSE Class 12 Board · 2005 · All India · Subjective