If `alpha` is the degree of dissociation of `Na_(2)SO_(4)`, the Vant 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-)),("Initial",1,,0,,0),("At equi.",1-alpha,,2alpha,,alpha):}`
van.t Hoffs factor, `i=(1-alpha+2alpha+alpha)/(1)`
`=1+2alpha`