What will be the `pH` at the equivalence point during the titration of a `100 mL 0.2 M` solution of `CH_(3)CCONa` with `0.2 M` solution of `HCl`? `K_(a)=2xx10^(-5)`

Options

A. `3-log sqrt2`
B. `3+log sqrt2`
C. `3-log 2`
D. `3+log 2`

Answer

A

Explanation

`underset(t_(eq)underset(t=0)(CH_(3)COONa)+underset(-)underset(20 meq)(HCl) rarr underset(-)underset(20 meq)(NaCl)+underset(20 meq)underset()(CH_(3)COOH)`
`[CH_(3)COOH]=(20)/(200)=0.1 M`
`pH=(1)/(2)[pK_(a)-logC]`
`=(1)/(2)[5-log2+1]`
`=(1)/(2)[6-log2]=3-logsqrt2`