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

• Hydrochloric acid (HCl) is monoprotic; thus, a 0.1 M solution yields 0.1 M H⁺ ions.
• Sulfuric acid (H₂SO₄) is diprotic; therefore, a 0.2 M solution provides 2 × 0.2 = 0.4 M H⁺ ions.

Upon mixing equal volumes, the total volume doubles, halving each acid's concentration:

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

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

The combined H⁺ concentration is:

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