It has been found that the `pH` of a `0.01 M` solution of an organic acid is `4.15`. Calculate the concentration of the anion, the ionization constant of the acid and its `pK_(a)`.

Explanation

`HA to H^(+) + A^(-)`
`pH=4.15=-log[H^(+)] implies[H^(+)]=[A^(-)]=7.079xx10^(-5)M`
`K_(a)=([H^(+)][A^(-)])/([HA]) =(7.079xx10^(-5)(7.079xx10^(-5)))/0.01=5.0xx10^(-7)`
`pK_(a)=-ogK_(a)=-log[5xx10^(-7)]=7-0.699=6.301`