The Van't Hoff factor for calcium nitrate `(Ca(NO_(3))_(2)` is 2.5 . Using the dissociation equilibrium,
`Ca(NO_(3))_(2) hArr Ca^(2+)+2NO_(3)^(-)`
the degree of dissociation is :

Options

A. 0.25
B. 0.33
C. 0.66
D. 0.75

Answer

D

Explanation

`Ca(NO_(3))_(2) hArr Ca^(2+)+2NO_(3)^(-)`
If a is the degree of dissociation,
`1-alpha " " alpha" "2alpha`
Total no. of particles after dissociation
`=1-alpha+alpha+2alpha=1+2alpha`
Van.t Hoff factor `=(1+2 alpha)/(1)=2.5`
`:.2 alpha=1.5` or `alpha=(1.5)/(2)=0.75`