Question

A 0.5 M NaOH solution has density 1.02 g mL^–1 . Its molality is: 

a. 0.51 m 

b. 0.49 m c. 0.50 m 

d. cannot be calculated

Answer 1

Correct option (C) 0.50 m

Explanation:

or mole of NaOH = 0.5 

mass NaOH = 20 gm 

mass of solution = v x d = 1000 x 1.02 = 1020 gm 

mass of solvent = 1020 – 20 = 1000 gm molality = 0.5 m