Question

Out of HCl and CH₃COOH, which one is a weak acid and why? Describe an activity to support your answer.

Answer 1

CH₃COOH is a weak acid when compared to HCl because HCl completely dissociates into ions in solution whereas CH₃COOH being weak acid is partially dissociated into ions in solution.

This can be proved by the following activity:

Two iron nails are fitted on a cork and are kept in a 100 mL beaker. The nails are then connected to the two terminals of a 6-volt battery through a bulb and a switch. Some dilute HCl is poured in the beaker and the current is switched on. The same experiment is then performed with CH₃COOH.

Observations:

It will be observed that the bulb glows in the HCl solution and does not glow in the CH₃COOH solution.

Inference:

HCl, being a strong acid dissociates into H⁺ and Cl⁻ ions. These ions conduct electricity in the solution resulting in the glowing of the bulb. On the other hand, the CH₃COOH is a weak acid. It does not dissociate into ions completely in solution. Therefore, it does not conduct electricity.