A scientist observes that after mixing a solid powder into water, the pH of the newly formed solution is 2.7. What can he infer from this observation?

The solution contains an indicator that has a pH of 2.7.

The solid powder contained hydrogen ions.

The pH indicator was used incorrectly.

The powder increased the hydrogen ion concentration of the solution.

I think the last option is the correct answer. The powder increased the hydrogen ion concentration of the solution. The said statement is the inference we can make from the situation. pH is the measure of hydrogen ions in a solution. The powder when added in the solution most likely dissociates into ions, especially hydrogen ions, thus decreasing the pH.