Question

Equal volumes of 0.25 M acetic acid and 0.25 M potassium hydroxide are combined. Write the net ionic equation for the reaction and identify the aqueous species that have the highest concentrations at equilibrium. Justify your answer.

Answer 1

Answer: The net ionic equation is $H^{+}(aq.)+OH^{-}(aq.)\rightarrow H_2O(l)$ and all the ions have equal concentrations at equilibrium

Explanation:

We are given:

Concentration of acetic acid = 0.25 M

Concentration of KOH = 0.25 M

Net ionic equation of any reaction does not include any spectator ions.

Spectator ions are defined as the ions which does not get involved in a chemical equation. They are found on both the sides of the chemical reaction when it is present in ionic form.

The chemical equation for the reaction of acetic acid and potassium hydroxide is given as:

$CH_3COOH(aq.)+KOH(aq.)\rightarrow CH_3COOK(aq.)+H_2O(l)$

Ionic form of the above equation follows:

$H^{+}(aq.)+CH_3COO^{-}(aq.)+K^{+}(aq.)+OH^{-}(aq.)\rightarrow K^+(aq.)+CH_3COO^-(aq.)+H_2O(l)$

As, potassium and acetate ions are present on both the sides of the reaction. Thus, it will not be present in the net ionic equation and are spectator ions.

The net ionic equation for the above reaction follows:

$H^{+}(aq.)+OH^{-}(aq.)\rightarrow H_2O(l)$

As, the mole ratio of acetic acid and potassium hydroxide in the reaction is 1 : 1. So, all the ions will have the equation concentration at equilibrium.

Hence, the net ionic equation is $H^{+}(aq.)+OH^{-}(aq.)\rightarrow H_2O(l)$ and all the ions have equal concentrations at equilibrium