A cetrain buffer solution contains equal concentration of `X^(-)` and HX. Calculate pH of buffer. `(K_(b)for X^(-)is 10^(-10))`

Explanation

We Know,
`:' K_(b(X^(-)))=10^(-10)`
also for conjugate acid pair
`K_(a_(HX))xxK_(b(X^(-)))=10^(-14)`
`K_(a[HX])=10^(-4)`
Now `underset(("acid"))([HX])=underset(("salt"))([X^(-)])`
`:. pH= -log K_(a)+log((["Salt"])/(["Acid"]))`
`= log 10^(-4)`
`pH= 4`