# Question #21243

Nov 20, 2016

Molarity (M) is defined as the number of moles of solute per liter of solution.
By definition we know

$\text{molarity"(M) = "moles of solute"/"liters of solvent}$
Here the molarity (M) is related with the volume of solution.Again the volume of solution increases with increase of temperature of the solution but number of solute remains unchanged.So molarity decreases with increase of temperature and increases with decrease in temperature.

Molality (m) is defined as the number of moles of solute per kilogram of solvent.

$\text{molality"(m) = "moles of solute"/"kilograms of solvent}$

In case of molality no change in number of moles of solute or the mass of solvent occurs with temperature.So moality remains unchanged with change in temperature.