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)/V)RT`
B. `M_=(m_/V)(RT)/pi`
C. `M_(2)=(m_(2)/V)piRT`
D. `M_(2)=(m_(2)/V)pi/(RT)`

Answer

2

Explanation

For dilute solutions, it has been found that the osmotic pressure is proportional to the molarity `(M)` of the solution at a given temperature `T`. Thus
`pi=MRT`
Here `pi` is the osmotic pressure and `R` is the gas constant.
or `pi=n_(2)/V RT`
where V is the volume of a solution in liters containing `n_(2)` moles of the solute. If `m_(2)` grams of solute, of molar mass, `M_(2)` is present in the solution, then `n_(2)=m_(2)//M_(2)` and we can write
`pi=m_(2)/(M_(2)V)RT`
or `M_(2)=(m_(2)/V) (RT)/pi`