To calculate the pH of a solution, we need to understand the relationship between pH and the hydrogen ion concentration [tex]\([H^+]\)[/tex] in a solution. The pH is a measure of the acidity or alkalinity of a solution.
Here is the detailed explanation:
The formula to calculate the pH is:
[tex]\[ \text{pH} = -\log_{10}([H^+]) \][/tex]
This formula states that the pH is equal to the negative base-10 logarithm of the hydrogen ion concentration [tex]\([H^+]\)[/tex].
Let's look at each of the given options to identify the correct one:
- Option A: "The pH is the negative log of [H+]."
- This option correctly defines the pH calculation as per the formula mentioned above.
- Option B: "The pH is the product of [H+] and [OH-]."
- This option is incorrect. The product of the concentrations of hydrogen ions [tex]\([H^+]\)[/tex] and hydroxide ions [tex]\([OH^-]\)[/tex] gives the ion product of water [tex]\(K_w\)[/tex], not the pH.
- Option C: "The pH is the log of [H+]."
- This option is incorrect because it does not include the negative sign, which is crucial in the pH calculation.
- Option D: "The pH is the negative log of [OH-]."
- This option is incorrect as the pH is related to the hydrogen ion concentration [tex]\([H^+]\)[/tex], not the hydroxide ion concentration [tex]\([OH^-]\)[/tex]. The negative logarithm of [tex]\([OH^-]\)[/tex] actually gives the pOH, not the pH.
Given the detailed analysis, the correct answer is:
Option A: "The pH is the negative log of [H+]."
