Question

The hydroxide ion concentration of a solution is $1.0\times {10}^{-9}$ M. What is the pH of this solution?

• A. 3
• B. 4
• C. 5
• D. 6

Answer 1

The correct option is C

5

pOH = $-lo{g}_{10}\left[O{H}^{-}\right]$

Therefore, according to the information given in the question,

pOH = $–lo{g}_{10}(1.0\times {10}^{-9})$

pOH = 9

pH = 14 – pOH

pH = 14 – 9 = 5

As, pH <7, so , the solution is acidic in nature.