Question

pOH of H2O is 7.0 at 298 K . If water is heated at 350 K, which of the following statement should be true?

• A. pOH will decrease.
• B. pOH will increase.
• C. pOH will remain 7.0.
• D. Concentration of H+ ions will increase but that of OH- will decrease.

Answer 1

Answer: (A)

pOH will decrease.

Answer 2

[OH–] = $\sqrt{K_{W}}$ in pure water.

So as temperature increases Kw decreases $\Rightarrow$ [OH–] decreases.