The acid-dissociation constant at 25.0°C for hypochlorous acid (HClO)is 3.0 × 10^-⁸.At equilibrium,the molarity of H₃O⁺ in a 0.010 M solution of HClO is ________. A) 1.7 × 10^-⁵ B) 0.010 C) 5.8 × 10^-¹⁰ D) 4.76 E) 2.00

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The acid-dissociation constant (Ka) for hypochlorous acid (HClO) is given as 3.0 × 10^-8. In a 0.010 M solution of HClO, the dissociation into H^+ and ClO^- ions at equilibrium can be represented by the equation HClO ⇌ H^+ + ClO^-. The equilibrium expression is Ka = [H^+][ClO^-]/[HClO]. Assuming x is the concentration of H^+ and ClO^- ions at equilibrium, Ka = x^2/(0.010 - x). Given that x is small compared to 0.010, we can approximate this to Ka = x^2/0.010. Solving for x gives the concentration of H^+ (and ClO^- by stoichiometry), which is approximately 1.7 × 10^-5 M, matching choice A.

The Acid-Dissociation Constant at 25