Find the `DeltapH(` initial `pH -` final `pH)` when `100 ml 0.01M HCl` is added in a solution containing `0.1m` moles of `NaHCO_(3)` solution of negligible volume `(k_(a_(1))=10^(-7),k_(a_(2))=10^(-11)` for `H_(2)CO_(3)) :`

Options

A. 6+2 log3
B. 6-log3
C. 6+2log2
D. 6-2log3

Answer

A

Explanation

pH of `NaHCO_3` solution =9 (initial)
Now `H^+ + HCO_3^(-) to H_2CO_3`
`:.` no . of mmole of HCl remaining =1-0.1=0.9 mmole
`:.` pH=-log `(9xx10^(-3))=-2 log 3+3` (Final)