Question

`K_(a)` for HCN is `5.0xx10^(-10)` at `25^(@)C`. For maintaining a constant pH of 9. Calculate the volume of `5.0M KCN` solution required to be added to 10 mL of `2.0M HCN` solution.

Answer 1

Correct Answer - 2
`pH= -log 5.0xx10^(-10)+log [(5xxV)/(V+10)//(10xx2)/(V+10)]`
or `9= -log 5.0xx10^(-10)+log (V)/(4)`
`:. V = 2 mL`