A 0.120 molal solution of CsCl[with ionizes in the solution as `CsClhArrCs^(+)+Cl^(-)`] freezes at `-0.4^(@)C`. The Van't Hoff factor and degree of dissociation of CsCl in the solution, respectively are (Given `K_(f)` (wate) =`1.86K kg "mol"^(-1)`)

Options

A. `1.79, 0.79`
B. `1.5,0.5`
C. `1.92,0.92`
D. `1.2,0.2`

Answer

A

Explanation

`DeltaT_(f)=ixxk_(f)xxm`
`T_(f)^(@)-T_(f)=1.86xxixx0.120`
`0.4=ixx0.2232`
`i=1.79`
`i=1+(n-1)alpha[n=2]`
`1.79=1+alpha`