A buffer solution contains 2.18M hypochlorous acid and 0.54M hypochlorite ion. What is the pH of the buffer? The Ka of hypochlorous acid is 4.0 x 10^-8.

1 Answer
Mar 22, 2018

We address the equilibrium...

#HOCl(aq) + H_2O(l) rightleftharpoons""^(-)OCl + H_3O^+#

Explanation:

.... for which....

#K_a=4.0xx10^-8=([""^(-)OCl][H_3O^+])/([HOCl(aq)])#

....and in the preparation of a buffer...then...

#pH=pK_a+log_10{([""^(-)OCl])/([HOCl(aq)])}#

And so #pH# should be TOLERABLY close to the #pK_a# of the acid ... it should be equal if #[HOCl]=[""^(-)OCl]#..

I leave it to you to extract the #pH# of this buffer....