If `P_0 and P_s` are the vapour pressure of solvent and solution, respectively and `N_1 and N_2` are the moles of solute and solvent then

Options

A. `(P_0-P_S)/(P_0)=(N_1)/(N_1+N_2)`
B. `(P_0-P_S)/(P_S) = N_1/N_2`
C. `P_S = P_0 * (N_2)/(N_1 +N_2)`
D. All of these.

Answer

D

Explanation

According to Raoult.s law,
`(P_0-P_S)/(P_0)=(N_1)/(N_1+N_2), :. 1- P_S/P_0 = (N_1)/(N_1 +N_2)`
or `P_S/P_0 = (N_1)/(N_1 +N_2)=N_2/(N_1+N_2) or P_S = P_0 xx(N_2)/(N_1 +N_2)`
Again, `(P_0-P_S)/(P_0)=(N_1)/(N_1+N_2)`
`:. P_0/(P_0-P_S) = (N_1+N_2)/N_1 = 1+N_2/N_1`
or `P_S/(P_0-P_S) = N_2/N_1 or (P_0-P_S)/P_S =N_1/N_2`