Answer:
[tex]0.25= \frac{[CN-]}{[HCN]}[/tex]
Explanation:
Henderson hasselbach equation
[tex]pH=pKa+log \frac{[A-]}{[HA]}[/tex][tex]pH=pKa+log \frac{[CN-]}{[HCN]}[/tex]
[tex]pH-pKa=log \frac{[A-]}{[HA]}[/tex]
pka= log Ka= log 4.9x10^-10= 9.3
[tex]9.9-9.3=log \frac{[CN-]}{[HCN]}[/tex]
[tex]0.6=log \frac{[CN-]}{[HCN]}[/tex]
[tex]10^{-0.6} = \frac{[CN-]}{[HCN]}[/tex]
[tex]0.25= \frac{[CN-]}{[HCN]}[/tex]
