The density of $3 \mathrm{M}$ solution of $\mathrm{NaCl}$ is $1.0 \mathrm{~g} \mathrm{~mL}^{-1}$. Molality of the solution is ____________ $\times 10^{-2} \mathrm{~m}$. (Nearest integer).
Given: Molar mass of $\mathrm{Na}$ and $\mathrm{Cl}$ is $23$ and $35.5 \mathrm{~g} \mathrm{~mol}^{-1}$ respectively.
Answer (integer)
364
Solution
$\mathrm{m}=\frac{1000 \mathrm{M}}{1000 \rho-\mathrm{M} . \mathrm{m_w}}=\frac{1000 \times 3}{1000-3 \times(58.5)}$ $=\frac{3000}{(1000-175.5)}=3.638$
<br/><br/>$=363.8 \times 10^{-2}$
<br/><br/>Nearest integer $=364$
About this question
Subject: Chemistry · Chapter: Some Basic Concepts of Chemistry · Topic: Mole Concept
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