Question

What is the main advantage of molality over molarity as unit of concentration ?

Answer 1

Molality: Molality is the numbers of moles of a given substance per kilogram of solvent (not solution).

Molarity: Molarity is the numbers of moles of a given substance in per litre solution.

Both are used to calculate the number of moles of solute. But By using molality term we can calculate number of moles of solutes in solvent, so it gives the advantage of knowing the number of moles of solute in solvent while in molarity we can only calculate number of moles of solute in solution ( per litre). Molality gives number of moles per kilogram while molarity gives number of moles per litre.