Equal weight of a certain non volatile non electrolyte solute is dissolved in equal weight of two solvents A and B to form very dilute solution. The relative lowering of vapour pressure for solution B is twice the relative lowering ofvapour pressure for solution A. `M_A and M_B` are the molecular mass of solvents A and Brespectively, then: a)M A = M B b)M B = 2 × M A c)M A = 4 M B d)M A = 2 M B

Options

A. `M_(A)= M_(B)`
B. `M_(B)= 2 xx M_(A)`
C. `M_(A) = 4M_(B)`
D. `M_(A)= 2M_(B)`

Answer

B

Explanation

`(P^(@)-P)/(P^(@))= (n)/(n+N) ~~ (n)/(N)` (for very dilute solution)
`2 xx (n)/(N_(A)) = (n)/(N_(B)) rArr M_(B)= 2m_(A)`