Which of the following statemetn is `//` are correct ?
`I`. Van't Hoff factor for `10^(-3) M CH_(3)COOH` is `39//35 (wedge^(@)._(m)=350 S cm^(2) mol^(-1)` and `k=4xx10^(-5) S cm^(-1)).`
`II.` If `wedge^(@)._(m)` of `KCl, LiCl,` and `KNO_(3)` are `150, 115, ` and `145 S cm^(2) mol^(-1),` then that of `LiNO_(3)` will be `110 S cm^(2) mo^(-1).`
`III.` In general, with increase in concentration, the specific conductance increases and reaches a maximum and then decreases with further increase in concentration.

Options

A. `I,II,` and `III`
B. `I` and `II`
C. Only `I`
D. Only `II`

Answer

A

Explanation

Statement `I` is correct `:`
`wedge_(m)^(c)=(kxx1000)/(M)=(4xx10^(-5)xx1000)/(10^(-3))=40`
`alpha=(wedge_(m)^(c))/(wedge_(m)^(c))=(40)/(350)=(4)/(35)`

`i(` van't Hoff factor `)=((1-alpha)+alpha+alpha)/(1)=1+alpha`
`i=1+alpha=1+(4)/(35)=(39)/(35)`
Statement `II` is correct `:`
`lambda^(@)._(m(LiNO_(3)))=lamda^(@)._(m(LiCl))+lambda^(@)._(m(KNO_(3)))-lambda^(@)._(m(KCl))`
`=115+145-150=110 S cm^(2) mol ^(-1)`
Statement `III` is correct `:(` Refer section `)` and Figure.