Question

the ph of a naoh solution is 12.05. what is the concentration of [oh-] of the naoh solution? express your answer in standard notation

Answer 1

0.0112

Step-by-step explanation:

They said that was the answer.

Answer 2

0.01 M

Step-by-step explanation:

NaOH (sodium hydroxide) is a strong base, so it is completely dissociated into ions in aqueous solution:

NaOH ⇄ Na⁺ + OH⁻

So, we have OH⁻ ions in solution.

From the problem, we have the pH value. The pH is calculated as:

pH = -log [H⁺]

As NaOH is a base, we can also calculate the pOH:

pOH = -log [OH⁻]

Thus. we can use the relation between pH and pOH to calculate the pOH and then use it to calculate [OH⁻]:

pH + pOH = 14 ⇒ pOH = 14 - pH = 14 - 12.05 = 1.95

pOH = -log [OH⁻] ⇒ [OH⁻] =
`10^(-pOH)`=
`10^(1.95)`= 0.0112 M ≅ 0.01 M