The pH of a buffer prepared by mixing 50 ml of `0.2 M CH_(3)COOH` and 25 ml of `CH_(3)COONa` is 4.8. If the `pK_(a)` is 4.8, what is the strength of `CH_(3)COONa`?

Explanation

The given solution is an acid buffer.
`:.` The pH of the buffer is given by,
`pH=[pK_(a)+log.(["Salt"])/(["Acid"])]`
`i.e, 4.8=4+8 log. (["Salt"])/(["Acid"]) rArr log. (["Salt"])/(["Acid"])=0.0`
`:. (["Salt"])/(["Acid"])=1.0` [Salt]=[Acid]
i.e., `(25xxM)/(75)=(50xx0.2)/(75) rArr M=(50xx0.2)/(25)=0.4M`
i.e., concentration of `CH_(3)COONa=0.4M`