Question

Equal volumes of aqueous solution of 0.1 M HCl and 0.2 M H₂SO₄ are mixed. The concentration of H+ ions in the resulting solution is:

• A. 0.15 M
• B. 0.30 M
• C. 0.10 M
• D. 0.25 M

Answer 1

The Correct Option is D

• HCl is a monoprotic acid, so 0.1 M HCl provides 0.1 M H⁺ ions.
• H₂SO₄ is a diprotic acid, so 0.2 M H₂SO₄ provides 2 × 0.2 = 0.4 M H⁺ ions.

When equal volumes of the two solutions are mixed, the total volume doubles, and the concentration of each acid is halved:

New concentration of HCl = \(\frac{0.1}{2} = 0.05 \text{M H}^+\)

New concentration of H₂SO₄ = \(\frac{0.4}{2} = 0.2 \text{M H}^+\)

The total H⁺ concentration is:

\( 0.05 \text{M} + 0.2 \text{M} = 0.25 \text{M} \)