What are the differences between molality and molarity?

Basis of differentiation

Molality

Molarity

Definition

Molality is a measure of the concentration of a solute in a solution, expressed in terms of the number of moles of solute per kilogram of solvent

The concentration of a solute in a solution, expressed as the number of moles of solute per liter of solution

Units

m

M

Formula

mole/kg

mole/L

Effect of temperature

It does not change with alterations in temperature

It increases with an increase in temperature

Dependence on mass

Depends on the mass of the solvent

Does not depend on the mass of the solvent

Effect of pressure

Is not affected by changes in pressure

Is affected by changes in pressure