Question

does density of 3 M solution of NaCl is 1.25 gram per ml calculate molality of solution

Answer 1

Given molarity 3M means 3 moles of NaCl are in 1000ml or 1 L water

molality means no. of moles of solute present per kg of solvent

density of solution is 1.25 g/ml

so wt of solution is 1.25 ×1000 = 1250 gm

wt of NaCl is 3×58.5 = 175.5

wt of solvent = 1250-205.5= 1074.5gm= 1.0445kg

molality = 3/1.0745 = 2.791m