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

Options

A. `(c)/(b) xx (1000)/((a - c))`
B. `(b)/(a) xx (1000)/((a - b))`
C. `(b)/(c) xx (1000)/((a - c))`
D. `(c)/(a) xx (1000)/((b - a))`

Answer

A

Explanation

Molality, `m = (w_(B))/(m_(B)) xx (1000)/(w_(A))`
`b = (c)/(m_(B)) xx (1000)/((a - c))`
`m_(B) = (c)/(b) xx (1000)/((a- c))`