Question

What is the concentration of a solution of 2,000 grams of water in which 684 grams of sucrose, $C_{12}{H}_{22}{O}_{11}$ is dissolved?

• A. 25 molar
• B. 0.5 molal
• C. 1 molal
• D. 5 molar
• E. 1 molar

Answer 1

The correct option is C 1 molal

The concentration of a solution of 2,000 grams of water in which 684 grams of sucrose, $C_{12}{H}_{22}{O}_{11}$ is dissolved is 1 molal.
Molar mass of sucrose is 342 g/mol. 684 g of sucrose corresponds to $\frac{684}{342}=2$ moles.
Mass of water is 2000 g or 2 kg. The molality of solution is the number of moles of sucrose present per kg of water. It is
$\frac{2mol}{2kg}=1m$