What is the hydrochloric acid concentration of a solution that has a pH of 2.9?

0.00126M

Explanation:

First, we need to obtain the H+ concentration. This is illustrated below:

pH = 2.9

pH = —Log [H+]

2.9 = —log [H+]

— 2.9 = Log [H+]

Anti log of —2.9 ie

[H+] = 10^—2.9

[H+] = 0.00126M

Now let us generate the dissociation equation of HCl. This is illustrated below:

HCl <==> H+ + Cl-

From the ionic equation,

Since 1 mole of H+ is produced by 1mole of HCl, this implies that 0.00126M of H+ will also be produce by 0.00126M of HCl.

Therefore the molarity of HCl is 0.00126M