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An aqueous KCl solution has density 1.20 g/mL and molality 3.30 mol/kg. Find its molarity (mol/L) to the nearest integer. (Molar mass of KCl = 74.5 g/mol.)

1. 3
2. 4
3. 2
4. 5

Correct answer: 3

Solution

Per kg water there are 3.30 mol KCl; total solution mass = 1245.85 g, volume = 1038.2 mL; molarity = 3.30/1.0382 ~ 3.18, nearest integer 3.

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