A certain weak acid has a dissociation constant `1.0xx10^(-4)`. The equilibrium constant for its reaction with a strong base is :

Explanation

`underset("Weak")(HA)+ underset("Strong")(BOH)hArr BA+H_(2)O`
`:. HA+B^(+)+OH^(-)hArr B^(+)+A^(-)+H_(2)O`
or `HA+OH^(-) hArr A^(-)+H_(2)O`
`:. K=([A^(-)])/([HA][OH^(-)])` …..(1)
Also for weak acid HA:
`HA hArr H^(+)+A^(-)`
`K_(a)=([H^(+)][A^(-)])/([HA])`
By eqs. (2) and (1),
`(K_(a))/(K)=K_(w)`
`K=(K_(a))/(K_(w))=(10^(-4))/(10^(-4))=10^(10)`