To find the hydronium ion concentration [tex]\(\left[ \text{H}_3\text{O}^+ \right]\)[/tex] of a solution given its pH, we use the formula:
[tex]\[
\left[ \text{H}_3\text{O}^+ \right] = 10^{-\text{pH}}
\][/tex]
Given that the pH of the solution is 3.60, we can substitute this value into the formula:
[tex]\[
\left[ \text{H}_3\text{O}^+ \right] = 10^{-3.60}
\][/tex]
Upon calculating [tex]\(10^{-3.60}\)[/tex], we get:
[tex]\[
\left[ \text{H}_3\text{O}^+ \right] \approx 0.00025118864315095795 \, M
\][/tex]
To express this result in scientific notation, we can rewrite it as:
[tex]\[
0.00025118864315095795 \, M = 2.5118864315095795 \times 10^{-4} \, M
\][/tex]
We typically round our final answer to two significant figures for simplicity, especially in the context of a multiple-choice question. Hence, we get:
[tex]\[
\left[ \text{H}_3\text{O}^+ \right] \approx 2.5 \times 10^{-4} \, M
\][/tex]
Thus, the correct answer to the problem is:
A. [tex]\(2.5 \times 10^{-4} \, M\)[/tex]
