Determine the ph of a 0.05 m solution of hydrocyanic acid (hcn). hydrocyanic acid has an acid-dissociation constant of 4.9 × 10-10.

Answer : The pH of a 0.05 M solution of hydrocyanic acid (HCN) is, 5.305

Solution :

The balanced equilibrium reaction will be,

The expression for dissociation constant will be,

Let the concentration of and will be, 'x'

That means the concentration of and are

Now we have to calculate the pH.

Therefore, the pH of a 0.05 M solution of hydrocyanic acid (HCN) is, 5.305