Vapour pressure of benzene is 200 mm of Hg. When 2 gram of a non-volatile solute dissolved in 78 gram benzene, benzene has vapour pressure of 195 mm of Hg. Calculate the molar mass of the solute. [Molar mass of benzene is 78 g/`mol^(-1)`]

Explanation

`M_B = (W_(B) xx M_(A))/(W_(A)) ((p_(A)^(@))/(p_(A)^(@) - P_(A))) = (2xx 78)/(78)((200)/(200-195))`
`M_(B) = 80 g " mol"^(-1)`