A solution contains non-volatile solute of molecular mass `M_(2)` which of the following can be used to calculate the molecular mass of solute in terms of osmotic pressure?
(`m_(2)` =mass of solute,V=volume of solution,`pi` =osmotic pressure)

Options

A. `M_(2)=[(m_(2))/(pi)]VRT`
B. `M_(2)=[(m_(2))/(V)](RT)/(pi)`
C. `M_(2)=[(m_(2))/(V)]pi RT`
D. `M_(2)=[(m_(2))/(V)](pi)/(RT)`

Answer

B

Explanation

For dilute solution,
`pV=nRT " " (p = pi, "osmotic pressure")`
or `pi V= nRT` or `pi=(n)/(V)RT`
`rArr pi V=(m_(2))/(M_(2))RT rArr M_(2)=(m_(2)RT)/(pi V)`
where, `pi` = osmotic pressure
V = volume of solution
n = number of moles of solute
`m_(2)` = mass of solute
`M_(2)` = molecular mass of solute