Calculate the pH of a solution that contains 2.4 × 10^-5 mol L^-1 H₃O⁺ at 25 °C. A) 2.40 B) 9.38 C) 4.62 D) 11.60 E) 4.17

Question

Quizplus · Accepted Answer

The first step in solving this problem is to write the acid dissociation reaction for HSO₄⁻:

HSO₄⁻ + H₂O ⇌ H₃O⁺ + SO₄²⁻

The acid dissociation constant, Ka, for this reaction is 1.02 × 10⁻².

Next, we need to use the concentration of HSO₄⁻ in the solution to calculate the concentration of H₃O⁺, which will allow us to find the pH of the solution.

We are given that the concentration of HSO₄⁻ is 2.4 × 10⁻⁵ mol/L. Since the acid dissociation reaction involves a 1:1 ratio of HSO₄⁻ to H₃O⁺, the concentration of H₃O⁺ will also be 2.4 × 10⁻⁵ mol/L.

Now we can use the concentration of H₃O⁺ to calculate the pH of the solution:

pH = -log[H₃O⁺]
pH = -log(2.4 × 10⁻⁵)
pH = 4.62

Therefore, the correct answer is choice C.

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