The dissociation constants of acetic acid and HCN at `25^(@)C` are `1.5xx10^(-4)` and `4.5xx10^(-10)` respectively. The equilibrium constant for the equilibrium.
`CN^(-)+CH_(3)COOH hArr HCN+CH_(3)COO^(-)`

Options

A. `3xx10^(-5)`
B. `3xx10^(-4)`
C. `3xx10^(4)`
D. `3xx10^(5)`

Answer

C

Explanation

`CH_(3)COOH hArr CH_(3)COO^(-)+H^(+)`
`K_(1)=([CH_(3)COO^(-)][H^(+)])/([CH_(3)COOH])`
`=1.5xx10^(-5)`
`HCN hArr H^(+)+CN^(-)`
`K_(2)=([CN^(-)][H^(+)])/([HCN])`
`=4.5xx10^(-10)`
`CN^(-)+CH_(3)COOH hArr HCN+CH_(3)COO^(-)`
`K=([HCN][CH_(3)COO^(-)])/([CN^(-)][CH_(3)COOH])`
`=(K_(1))/(K_(2))=(1.5xx10^(-5))/(4.5xx10^(-10))~~0.3xx10^(5)`
`K=3xx10^(4)`