Question

A solution weighing 'a' $g$ has molality ' $b$ '. The molecular mass of solute, if the mass of solute is ' $c$ ' $g$, will be

• A. $\frac{c}{b} \times \frac{1000}{(a-c)}$
• B. $\frac{b}{a} \times \frac{1000}{(a-b)}$
• C. $\frac{b}{c} \times \frac{1000}{(a-c)}$
• D. $\frac{c}{a} \times \frac{1000}{(b-a)}$

Answer 1

Answer: (A)

Molality, $m=\frac{w_{B}}{m_{B}} \times \frac{1000}{w_{A}}$

$b=\frac{c}{m_{B}} \times \frac{1000}{(a-c)}$;

$ m_{B}=\frac{c}{b} \times \frac{1000}{(a-c)}$