Question

Question: Calculate the pH of a 5.0 × 10^-3 M solution of H₂SO₄.

Short answer

Answer

pH of 5.0 × 10^-3 M solution ofH₂SO₄ solution is 2.

Step-by-step solution

Calculation of [H+] Concetration

H₂SO₄ is a very strong acid so it dissociates completely.

${\text{H}}_{\text{2}}{\text{SO}}_{\text{4}}\rightleftharpoons 2{\text{H}}^{\text{+}}\text{+ S}{{\text{O}}_{\text{4}}}^{\text{2 -}}$

That means one H₂SO₄ molecule will give 2 H⁺ ions.

${\text{[H}}^{\text{+}}]=2\times 5\times {10}^{-3}={10}^{-2}\text{M}$

pH Calculation

pH can be calculated as:

$pH=-log\left[{\text{H}}^{\text{+}}\right]=-\log ({10}^{-2}\text{) = 2}$