The obsrved osmotic pressure foe a `0.10` M solution of `Fe (NH_(4))_(2) (SO_(4)) _(2)` at `25^(@)C` is `10.8` atm. The expected and experimental (observed) values of van't Hoff factor (i) will be respectively .

Options

A. 5 and `4.42`
B. `4 and 4.00`
C. 5 and `3.42`
D. `3 and 5.42`

Answer

A

Explanation

Given `pi _(ab)= 10.8` atm
`pi _(nw) =CST =0.10 xx0.0821 xx298 =2.446`
now experimental value of (i)
`= ("Observed osmotic pressure")/("Normal osmotic pressure") = (10.8)/(2.445) =4.42`