Question

Which aqueous solution has greater concentration - 1 molar or 1 molal of the same solute ? Give reason.

Answer 1

1 molar aqueous solution is more concentrated than 1 molal aqueous solution because 1 molar solution contain 1 mole of solute in 1 litre of the solution which include both solute and solvent. So, the mass of solvent (i.e. water) is less than 1000 gram. Therefore 1 molar aqueous solution contains 1 mole of solute in less than 1000 gram of solvent whereas 1 molal solution has 1 mole of solute in 1000 gram of solvent. Hence concentration will be more in 1 molar aqueous solution.