Hydrochloric acid is a strong acid. Acetic acid is a weak acid. Which statement about hydrochloric acid and acetic acid is correct?(1 point)

Question

Responses

The dissociation constant for hydrochloric acid is greater than the dissociation constant for acetic acid.
The dissociation constant for hydrochloric acid is greater than the dissociation constant for acetic acid.

The pH of a solution of hydrochloric acid must be less than the pH of a solution of acetic acid.
The pH of a solution of hydrochloric acid must be less than the pH of a solution of acetic acid.

A solution of hydrochloric acid at equilibrium will have a greater concentration of solute than a solution of acetic acid at equilibrium.
A solution of hydrochloric acid at equilibrium will have a greater concentration of solute than a solution of acetic acid at equilibrium.

If the initial concentration of each acid is the same, then acetic acid will produce more H3O+ ions than hydrochloric acid.

Answer 1

Let's analyze the statements one by one based on the properties of strong and weak acids:

1. The dissociation constant for hydrochloric acid is greater than the dissociation constant for acetic acid.

   • This statement is correct. Hydrochloric acid (HCl) is a strong acid that completely dissociates in water, leading to a very high dissociation constant (Ka), while acetic acid (CH₃COOH) is a weak acid with a much lower dissociation constant.

2. The pH of a solution of hydrochloric acid must be less than the pH of a solution of acetic acid.

   • This statement is also correct in general. Since HCl is a strong acid and completely dissociates to produce more H₃O⁺ ions than acetic acid (which does not fully dissociate), the pH of HCl will be lower than that of a solution of acetic acid (with the same initial concentration).

3. A solution of hydrochloric acid at equilibrium will have a greater concentration of solute than a solution of acetic acid at equilibrium.

   • This statement is misleading. While HCl does produce more H₃O⁺ ions than acetic acid, the concentration of solute could refer to the total concentration of the undissociated acid and the ions produced. If both solutions start with the same initial concentration, the total number of solute particles will depend on the degree of dissociation of the weak acid.

4. If the initial concentration of each acid is the same, then acetic acid will produce more H₃O⁺ ions than hydrochloric acid.

   • This statement is incorrect. Given the same initial concentration, hydrochloric acid will produce more H₃O⁺ ions because it completely dissociates, while acetic acid only partially dissociates.

Conclusion: The most universally correct statements are:

• The dissociation constant for hydrochloric acid is greater than the dissociation constant for acetic acid.
• The pH of a solution of hydrochloric acid must be less than the pH of a solution of acetic acid.

If only one response is to be chosen, the first statement regarding dissociation constants is the most direct and objectively correct answer.