Question

The density of 3m solution of nacl is 1.25g/l. calculate molality of the solution

Answer 1

molarity 3M means 3 moles of NaCl are in 1000ml or 1 L watermolality means no. of moles of solute present per kg of solventdensity of solution is 1.25 g/ml =>wt of solution is 1.25 ×1000 = 1250 gmwt of NaCl is 3×58.5 = 175.5wt of solvent = 1250-205.5= 1074.5gm= 1.0445kgmolality = 3/1.0745 = 2.791m