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

Answer

A

Explanation

`Na_(2)SO_(4)hArr2Na^(+)+SO_(4)^(2-)`
van't Hoff factor, `i=[1+(y-1)alpha]`
where, Y is the number of ions from one mole solutio, (in this case = 3 )`alpha` is the degree of dissociation `i=(1+2alpha)`