Mole fraction of a solution in 1.00 molal aqueous solution is

Options

A. `0.1770`
B. `0.0177`
C. `0.0344`
D. `0.83`

Answer

B

Explanation

For electrolytes, `Delta T_(f)=ixxk_(f)xxm` (min molarity)
or `Delta T_(f)=ixxk_(f)xx(W_(2))/(M_(2))xx(1000)/(W_(1)), Delta T_(f)=3.82^(@)C`
`k_(f)=1.86 K kg mol^(-1), M_(2)=142` for `Na_(2)SO_(4)`
`W_(2)=5g, W_(1)=45.0g`
`therefore 3.82=ixx1.86xx(5)/(142)xx(1000)/(45)`
`therefore i=(3.82xx142xx45)/(1.86xx5xx1000)=2.63`