The weight in grams of a non-volatile solute (molar mass = 60) to be dissolved in 90g of water to produce a relative of V.P. of 0.02 is

Options

A. 4
B. 8
C. 6
D. 10

Answer

C

Explanation

`(p_(1)^(o)-p)/p_(1)^(o) = x_(2) = (W_(2)//M_(2))/(W_(1)//M_(1)) = (W_(2) xx M_(1))/(W_(1) xx M_(2))`
`0.02 = (W_(2) xx 18 xx 10^(-3) kg mol^(-1))/(90 xx 10^(-3) kg xx 60 xx 10^(-3) kg mol^(-1))`
`:. W_(2) = (0.02 xx 60 xx 90 xx 10^(-3))/18 kg = 6 xx 10^(-3) kg = 6g`