Final answer:
To calculate the pH of a solution with a hydroxide ion concentration of 1.0 x 10⁻⁵ M, first calculate the pOH, which is 5, then subtract this from 14 to get a pH of 9, indicating the solution is basic. The correct option is 3.
Step-by-step explanation:
To calculate the pH of a solution from its hydroxide ion (OH-) concentration, you can first calculate the pOH, which involves taking the negative logarithm of the hydroxide ion concentration. For a solution with a hydroxide ion concentration of 1.0 x 10⁻⁵ M, the pOH can be calculated as follows:
pOH = -log(1.0 x 10⁻⁵) = 5
After determining the pOH, the pH can be found by subtracting the pOH from 14:
pH will be 14 - pOH
= 14 - 5
= 9
Thus, the pH of the solution is 9, which indicates that the solution is basic because it is greater than 7.
Hence, Option 3 is correct.