Question

$250$ $g$ solution of $D-glucose$ in water contains 10.8% of carbon by weight. The molality of the solution is nearest to (Given: Atomic Weights are, $H, 1 u; C, 12 u; O, 16 u$)

• A. 1.03
• B. 2.06
• C. 3.09
• D. 5.40

Answer 1

Answer: (B)

2.06

Answer 2

Weight of D-glucose in water =$250$ $g$
∴ Weight of carbon in D-glucose

= $\frac{250}{180}×72 = 100$ $g$

Percentage of carbon in the aqueous solution of glucose is

= $10.8\%$

∴ Weight of the solution is = $925.93$
∴ Molality of D-glucose is

=$\frac{\frac{ 250}{180}}{(925.93 - 250)}×1000$

= $\frac{250}{180×675.93} ×1000$

= $2.06$

Hence, the correct option is (B): $2.06$