Question

A solution has a [OH−] of 1 x 10^−12 M. What is the [H3O+] of the solution? a1 x 10^−14 M b1 x 10^−2 M c2 M d14 M

Answer 1

ANSWER

$\text{ }\lbrack H_3O^+\rbrack\text{ = 1}\times\text{ 10}^{-2}M$

EXPLANATION

Given that

The concentration of [OH-] is 1 x 10^-12M

Follow the steps below to find the concentration of [H3O+]

Step 1; Write the pOH formula

$\text{ pOH = -log }\lbrack OH^-\rbrack$$\begin{gathered} \text{ pOH = -log }\lbrack1\text{ }\times\text{ 10}^{-12}\rbrack \\ \text{ pOH = 12} \end{gathered}$

Step 2; Find the pH of the substance

Recall, that pH + pOH = 14

pOH = 12

pH + 12 = 14

subtract 12 from both sides of the equation

pH + 12 - 12 = 14 - 12

pH = 2

Step 3; Find the [H3O+] using the below formula

$\begin{gathered} \text{ pH = -log }\lbrack H_3O^+\rbrack \\ \text{ 2 = -log }\lbrack H_3O^+\rbrack \\ \text{ }\lbrack H_3O^+\rbrack\text{ = 10}^{-2} \\ \text{ }\lbrack H_3O^+\rbrack\text{ = 1 }\times\text{ 10}^{-2}\text{ M} \end{gathered}$

Therefore, the correct answer is option B