In: Chemistry
What is the pH of a 2.62 x 10 -1 M HCN solution? NB the pKa for HCN = 9.212.
pKa = 9.212
- LogKa = 9.212
Ka = 10-9.212
Ka = 6.14 * 10-10
Accoding to Ostwald's theory of weak acids,
[H+] = sqrt.(KA* C)
= sqrt.(6.14 * 10-10 * 2.62 * 10-1)
= 1.27 * 10-5 M
Therefore,
pH = - Log[H+]
= - log(1.27 * 10-5)
= 4.90