Question

Determine the Henry’s law constant for ammonia in water at 25 ºC if an ammonia
pressure of 0.022 atm produces a solution with a concentration of 1.3 M.

Answer 1

Concepts and reason

Solubility:

It is a chemical property which refers to the capacity of a given substance and the solute to be dissolved in a solvent. It is usually measured as the maximum amount of solute is dissolved in a solvent.

Henry’s law:

Henry’s law relates the solubility of a gas in liquid to the partial pressure of the gas.

The law states that at a constant temperature, the amount of a given gas that dissolves in a given type and volume of liquid is directly proportional to the partial pressure of that gas in equilibrium with that liquid.

Fundamentals

According to the Henry’s law the solubility of the gas in a given liquid is shown as follows.

Here,

The concentration of dissolved gas at fixed temperature in a particular solvent is .

The Henry’s law constant is .

The partial pressure of the gas is .

The given information in the problem is written down.

$Partial pressure of ammonia, PNHi, = 0.022 atm Concentration of ammonia,C\H, =1.3M Temperature, T 25 °C $

The Henry’s equation can be rearranged to Henry’s law constant as follows.

Rearranged to .

The value of Henry’s law constant is calculated as shown below.

Substitute for and for .

So, the Henry's law constant for is .

Ans:

The Henry's law constant for in water at the given temperature is .