If `pK_(a) = 4` at a particular temperature then van't Hoff factor,i for 0.01M monobasic acid is,

Options

A. `1.01`
B. `1.02`
C. `1.10`
D. `1.20`

Answer

C

Explanation

`pK_(a) = 4`
`-log_(10)K_(a) = 4`
`K_(a) = 10^(4-)`
`{:(,HA,overset("water")hArr,H^(+),+A^(-)),("Initial",0.01M,,,),("At eqm.",(0.01-x)M,,xM,xM):}`
As the solution is quite dilute
`K_(a) = (x^(2))/(0.01) = 10^(-4)`
`x^(2) = 10^(-2)`
`x = 10^(-1) = 0.1`
`i =(1-x+x+x)/(1)`
`= (1+x)/(1) = (1+0.1)/(1) = 1.1`