If `alpha `is the degree of dissociation of `N_(2)SO_(4)`, the van'tHoff factor (i) used for calculating the molecular mass is

Options

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

Answer

B

Explanation

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