At a particular temperature, the vapour pressures of two liquids A and B are respectively 120 and 180 mm of mercury. If 2 moles of A and 3 moles of B are mixed to form an ideal solution, the vapour pressure of the solution at the same temperature will be in mm of mercury)

Options

A. 156
B. 145
C. 150
D. 108

Answer

A

Explanation

`P_T= P_A^@ X_A + P_B^@ X_B`
`P_A^@ = 120 mm Hg, " " X_A= 2//5`
`P_B^@= 180 mm Hg, " " X_B = 3//5`
`P_T= 120xx2/5+180xx3/5 = 48 + 108 = 156 mm Hg`