Final answer:
The concentration of H3O+ ions in a 0.1 M solution of hydrofluoric acid with a pH of 2.1 is approximately 0.00794 M.
Step-by-step explanation:
The pH of a solution is a measure of its acidity or alkalinity. In this case, a 0.1 M solution of hydrofluoric acid (HF) has a pH of 2.1. The concentration of H3O+ ions in the solution can be determined using the equation: pH = -log[H3O+].
Therefore, rearranging the equation, we can find the concentration of H3O+ ions: [H3O+] = 10^(-pH). Substituting the given pH value of 2.1 into the equation, we get [H3O+] = 10^(-2.1), which is approximately 0.00794 M.
So, the concentration of H3O+ ions in the 0.1 M solution of HF is approximately 0.00794 M.