Question

state the main advantage of molality over molarity as the unit of concentration

Answer 1

molality does not change with temperature

Answer 2

Answer: Molality does not change with any change in the temperature.

Explanation:

Molarity is defined as the amount of solute present in 1 liter of the solution. As, volume is dependent on temperature and if there is any change in temperature, volume will also change and hence, the molarity of the solution will change.

$Molarity=\frac{w_{solute}}{M_{Solute} \times V_{Solution}\text{(in L)}}$

Molality is defined as the amount of solute present in 1 kg of solvent. As, mass is not dependent on temperature. So, if there is any change in the temperature, the molality will remain the same.

$Molality=\frac{w_{solute}}{M_{Solute} \times w_{Solvent}\text{(in kg)}}$

As, molality remains the same with change in temperature and hence it has an advantage over molarity.