Question

A student measured the pH of solutions of hydrochloric acid and ethanoic acid. Both solutions had the same volume and concentration. The pH of hydrochloric acid was 1.0. The pH of ethanoic acid was 2.9. The hydrogen ion concentration of hydrochloric acid was 0.1 mol/dm³. What is the approximate hydrogen ion concentration of ethanoic acid?

a) 0.001 mol/dm³
b) 0.01 mol/dm³
c) 0.1 mol/dm³
d) 1 mol/dm³

Answer 1

The hydrogen ion concentration of ethanoic acid is less than 0.1 mol/dm³. The approximate hydrogen ion concentration of ethanoic acid is 0.001 mol/dm³.

Step-by-step explanation:

The pH of a solution is a measure of its acidity. It is determined by the concentration of hydrogen ions (H+) in the solution. A lower pH value indicates a higher concentration of hydrogen ions and a higher acidity.

In this case, the hydrochloric acid solution has a pH of 1.0, which means it has a higher hydrogen ion concentration compared to the ethanoic acid solution, which has a pH of 2.9. From this information, we can infer that the hydrogen ion concentration of the ethanoic acid solution is lower than 0.1 mol/dm³.

Based on the given options, the approximate hydrogen ion concentration of ethanoic acid is less than 0.1 mol/dm³. Therefore, the correct answer is (a) 0.001 mol/dm³.