Question

fill in the left side of this equilibrium constant equation for the reaction of nitrous acid (hno₂) with water. = kₐ

Explanation:

Step1: Write the dissociation reaction of nitrous acid

Nitrous acid (\(HNO_2\)) reacts with water (\(H_2O\)) as follows: \(HNO_2(aq)+H_2O(l)
ightleftharpoons NO_2^-(aq) + H_3O^+(aq)\)

Step2: Recall the formula for acid - dissociation constant (\(K_a\))

The formula for \(K_a\) is \(K_a=\frac{[products]}{[reactants]}\). For the reaction \(HNO_2(aq)+H_2O(l)
ightleftharpoons NO_2^-(aq) + H_3O^+(aq)\), water (\(H_2O\)) is a pure liquid and its concentration is omitted from the equilibrium - constant expression. So, \(K_a=\frac{[NO_2^-][H_3O^+]}{[HNO_2]}\)

Answer:

\(\frac{[NO_2^-][H_3O^+]}{[HNO_2]}\)