A0.50 m solution of an unknown acid has a ph = 4.0. of the following, which is the acid in the solution?

hocl (ka = 2.0 x 10-8)
hbr (strong acid)
hf (ka = 6.8 x 10-4)
c6h5oh (ka = 1.0 x 10-10)

,

Explanation:

pH is defined as the negative logarithm of the concentration of hydrogen ions.

Thus,  

pH = - log [H⁺]

Strong acids dissociate completely and thus, 0.5 M of a solution of a strong acid yields a pH of 1.0 .

The expression of the pH of the calculation of weak acid is:-

Where, C is the concentration = 0.5 M

Given, pH = 4.0

So, for ,

pH = 4.0

Hence, the acid is HOCl.