If `alpha` is the degree of dissociation of `Na_(2)SO_(4)` the van't Hoff's factor (i) used for calculating the molecular mass is

Options

A. `1+alpha`
B. `1-alpha`
C. `1+2alpha`
D. `1-2alpha`

Answer

C

Explanation

`{:(Na_(2)SO_(4),hArr,2Na^(+),+,SO_(4)^(2-)),("Mol. before diss. 1",,0,,0),("Mol. after diss " 1-alpha,,2alpha,,1alpha):}`
`i=(Exp. C.P.)/("Normal C.P.")=1-alpha+2alpha+alpha=1+2alpha`