What is the pH of ferric sulfate?

The pH of ferric sulfate, a salt formed by the reaction of iron(III) sulfate and water, is typically on the lower end of the pH scale due to its acidic nature when dissolved in water. Ferric sulfate hydrolyzes to release hydrogen ions (H⁺), contributing to a more acidic solution. As a result, the pH tends to be acidic, commonly ranging around 1.0 to 3.0, depending on the concentration of the solution.

In this context, choosing a pH of 1.0 reflects the stronger acidic property of ferric sulfate in solution, particularly in more concentrated forms, making it the most accurate among the options provided. Values of 7.4 and 5.5 would indicate neutral to slightly acidic solutions, which would not accurately represent ferric sulfate's behavior in water due to its hydrolysis and the release of hydrogen ions. The option of 3.0, while closer to real-world scenarios in some diluted solutions, does not capture the more concentrated, typically more acidic state ferric sulfate can create. Thus, the choice of 1.0 effectively highlights the strong acidity associated with ferric sulfate in aqueous conditions.