Question

write the concentration equilibrium constant expression for this reaction.

hf(aq)+h₂o(l)→f⁻(aq)+h₃o⁺(aq)

Explanation:

Step1: Recall the formula for equilibrium constant

For a reaction \(aA + bB
ightleftharpoons cC + dD\), \(K_c=\frac{[C]^c[D]^d}{[A]^a[B]^b}\), where \([X]\) is the concentration of species \(X\).

Step2: Identify the reactants and products

In the reaction \(HF(aq)+H_2O(l)
ightleftharpoons F^-(aq)+H_3O^+(aq)\), the reactants are \(HF\) (aqueous) and \(H_2O\) (liquid). The products are \(F^-\) (aqueous) and \(H_3O^+\) (aqueous).

Step3: Apply the formula

Since \(H_2O(l)\) is a pure liquid, its concentration is omitted from the equilibrium - constant expression. For the reaction \(HF(aq)
ightleftharpoons F^-(aq)+H_3O^+(aq)\) (after omitting \(H_2O(l)\) as per the rules for heterogeneous equilibria), using the formula \(K_c=\frac{[products]}{[reactants]}\), we get \(K_c=\frac{[F^-][H_3O^+]}{[HF]}\)

Answer:

\(K_c=\frac{[F^-][H_3O^+]}{[HF]}\)