Indicate whether aqueous solutions of each of the following solutes contain only ions, only molecules, or mostly molecules and a few ions: a. acetic acid, HC₂H₃O₂, a weak electrolyte

Verified step by step guidance

1. Identify the type of solute: Acetic acid (HC₂H₃O₂) is a weak acid and a weak electrolyte.
2. Understand the behavior of weak electrolytes: Weak electrolytes partially dissociate into ions in solution.
3. Write the dissociation equation: HC₂H₃O₂ (aq) ⇌ H⁺ (aq) + C₂H₃O₂⁻ (aq).
4. Recognize the equilibrium: In an aqueous solution, the equilibrium lies far to the left, meaning most of the acetic acid remains as molecules.
5. Conclude the composition: The solution contains mostly molecules and a few ions.

Key Concepts

Weak Electrolytes

Weak electrolytes are substances that partially dissociate into ions when dissolved in water. Unlike strong electrolytes, which completely ionize, weak electrolytes exist in equilibrium between their molecular form and their ionic form. This means that in a solution of a weak electrolyte, such as acetic acid, there will be a mixture of both ions and un-ionized molecules.

Dissociation in Aqueous Solutions

Dissociation refers to the process by which a compound separates into its constituent ions in a solvent, typically water. In the case of acetic acid, HC₂H₃O₂, it dissociates into acetate ions (C₂H₃O₂⁻) and hydrogen ions (H⁺) to a limited extent. The degree of dissociation is crucial for determining the composition of the solution, as it influences whether the solution contains mostly molecules or ions.

Equilibrium in Chemical Reactions

Equilibrium in chemical reactions occurs when the rate of the forward reaction equals the rate of the reverse reaction, resulting in constant concentrations of reactants and products. For weak electrolytes like acetic acid, this means that there is a dynamic balance between the dissociated ions and the undissociated molecules. Understanding this concept helps in predicting the behavior of weak acids in solution, including their ionization and the resulting composition.