Question

A solution of sodium sulfate contains $92\, g$ of ${Na^{+}}$ ions per kilogram of water. The molality of ${Na^{+}}$ ions in that solution in ${mol \; kg^{-1}}$ is:

• A. 16
• B. 8
• C. 4
• D. 12

Answer 1

Answer: (C)

4

Answer 2

$n_{Na^{+}} = \frac{92}{23} = 4$
So molality = 4