The equilibrium equation and `K_(a)` values for the three acids are given at `25^(@)C`:
`HA(aq)+H_(2)OhArrH_(3)O^(+)(aq)+A^(-)(aq),K_(a)=2xx10^(-5)`
`HB(aq)+H_(2)OhArrH_(3)O^(+)(aq)+B^(-)(aq),K_(a)=4xx10^(-6)`
`HC(aq)+H_(2)OhArrH_(3)O^(+)(aq)+C^(-)(aq),K_(a)=1xx10^(-4)`
Which conjugate pair would be best for preparing a buffer witha pH =54? (log 2=0.3).

Options

A. `HA+A^(-)`
B. `HB+B^(-)`
C. `HC+C^(-)`
D. `H_(2)O+H_(3)O^(+)`

Answer

b