Hypochlorous acid (HOCl) has an ionization constant of 3.2 × 10^-8. What is its percent ionization in 1.0 M and 0.10 M solutions, respectively? A) 0.018% and 0.057% B) 0.032% and 0.0032% C) 0.57% and 0.18% D) 0.57% in both E) 0.32% in both

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Quizplus · Accepted Answer

The percent ionization of a weak acid can be calculated using the following equation:% ionization = [H+]/[HA] x 100%where [H+] is the molar concentration of hydrogen ions and [HA] is the molar concentration of the weak acid.For HOCl, the ionization constant is 3.2 x 10^-8. This means that in a 1.0 M solution of HOCl, the concentration of hydrogen ions will be:[H+] = sqrt(Ka x [HA]) = sqrt(3.2 x 10^-8 x 1.0) = 1.8 x 10^-4 MThe percent ionization will then be:% ionization = [H+]/[HA] x 100% = (1.8 x 10^-4 M)/(1.0 M) x 100% = 0.018%In a 0.10 M solution of HOCl, the concentration of hydrogen ions will be:[H+] = sqrt(Ka x [HA]) = sqrt(3.2 x 10^-8 x 0.10) = 5.7 x 10^-5 MThe percent ionization will then be:% ionization = [H+]/[HA] x 100% = (5.7 x 10^-5 M)/(0.10 M) x 100% = 0.057%

Hypochlorous Acid (HOCl) Has an Ionization Constant of 3