Question

Which of the following statement is true?

• A. Molarity of solution is independent of temperature
• B. Molality of solution is independent of temperature,
• C. Mole fraction of solute is dependent on temperature
• D. The unit of molality is $mold{m}^{-3}$

Answer 1

Answer: (B)

(1) $M=\frac{w}{M_w\times V(L)}$
$M\propto \frac{1}{\text{ Volume }}$
$M$ - Depends on volume so it also depends on temperature. $PV=nRT$
(2) Molality $=\frac{w}{M_w\times W_{\text{solvent }}(kg)}$
Molality does not depend on volume so it does not depend on temperature.
(3) Mole fraction also does not depend on volume, so not on temperature
(4) $m=\frac{w}{M_w\times w_{\text{solvent }(kg)}}$
$=\frac{mol}{kg}\left(not\to \frac{mol}{d{m}^3}\right)$