Question

The acid-dissociation constant (Ka​) of chlorous acid (HClO₂​) is 1.1×10⁻². Calculate the concentrations of H⁺, ClO₂⁻​, and HClO₂​ at equilibrium if the initial concentration of HClO₂​ is 0.0125M.

Answer 1

The concentrations of H+, ClO2-, and HClO2 at equilibrium are calculated using an ICE table and the given Ka value of chlorous acid, leading to a quadratic equation that must be solved for 'x.'

Step-by-step explanation:

To calculate the concentrations of H+, ClO2−, and HClO2 at equilibrium for chlorous acid with a Ka value of 1.1×10−2 and an initial concentration of 0.0125 M, we can use an ICE (Initial, Change, Equilibrium) table. Set up the equilibrium expression based on the dissociation of HClO2:
HClO2 → H+ + ClO2−.

Using the ICE table, assume that 'x' represents the change in concentration due to the dissociation of HClO2. At equilibrium, we have:
[H+] = [ClO2−] = x
[HClO2] = 0.0125 - x.
Then substitute these expressions into the Ka expression:

Ka = (x)(x) / (0.0125 - x) = 1.1×10−2

To simplify calculations, we can assume that x is much smaller than 0.0125 M. Solving this quadratic equation gives us x, and substituting 'x' back into the equilibrium expressions provides the concentrations of H+, ClO2−, and HClO2.