A buffer solution contains 0.1 mole of sodium acetate dissolved in `1000cm^(3)` of 0.1 M acetic acid. To the above buffer solution, 0.1 mole of sodium acetate is further added and dissolved. The pH of the resulting buffer is :

Options

A. `pK_(a)-log 2`
B. `pK_(a)`
C. `pK_(a)+2`
D. `pK_(a)+log2`

Answer

D

Explanation

`pH_("Initial") = pK_(a) +log. (["Salt"])/(["Acid"])`
`pH _("Initial")=pK_(a) + log. ((0.1))/((0.1))`
`pH_("Initial") = pK_(a)`
`pH _("final") =pK_(a) + log. ((0.2))/((0.1))`
`pH_("final")= pK_(a)+log 2 `.