What is the hydronium ion concentration of a 0.100 M acetic acid solution with a K_a = 1.8 × 10^-5? The equation for the dissociation of acetic acid is: CH₃CO₂H(aq)+ H₂O(l)⇌ H₃O⁺(aq)+ CH₃CO₂^-(aq). A)1.3 × 10^-2 M B)4.2 × 10^-2 M C)1.3 × 10^-3 M D)4.2 × 10^-3 M

Question

Quizplus · Accepted Answer

The equilibrium constant (Ka) for the dissociation of acetic acid can be expressed as follows:
Ka = [H3O+][CH3COO-]/[CH3COOH]
We can assume that the concentration of CH3COO- = [H+] and substitute the given values:
1.8 × 10-5 = [H+]2/0.1
[H+]2 = 1.8 × 10-6
[H+] = sqrt(1.8 × 10-6)
[H+] = 1.34 × 10-3 M
Therefore, the hydronium ion concentration of the solution is 1.3 × 10-3 M, which is closest to option C.

What Is the Hydronium Ion Concentration of a 0