$250 \mathrm{~g}$ solution of $\mathrm{D}$-glucose in water contains $10.8 \%$ of carbon by weight. The molality of the solution is nearest to
(Given: Atomic Weights are, $$\mathrm{H}, 1 \,\mathrm{u} ; \mathrm{C}, 12 \,\mathrm{u} ; \mathrm{O}, 16 \,\mathrm{u}$$)
Solution
Weight of D-glucose in water $=250 \mathrm{~g}$
<br/><br/>
$$
\begin{aligned}
\therefore \text { Weight of carbon in D-glucose } &=\frac{250}{180} \times 72 \\\\
&=100 \mathrm{~g}
\end{aligned}
$$
<br/><br/>
$\%$ of carbon in the aqueous solution of glucose is $=10.8 \%$
<br/><br/>
$\therefore$ Weight of the solution is $=925.93$
<br/><br/>
$$
\begin{aligned}
\therefore \text { Molality of D-glucose is } &=\frac{\frac{250}{180}}{(925.93-250)} \times 1000 \\\\
&=\frac{250}{180 \times 675.93} \times 1000 \\\\
&=2.06
\end{aligned}
$$
About this question
Subject: Chemistry · Chapter: Some Basic Concepts of Chemistry · Topic: Mole Concept
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