4. If a solution’s pOH changes from 11 to 13, what does this indicate about the change in concentration of hydronium ions in that solution? Include specific quantitative information in your answer.

Answer 1

Where to start:

Identify what is pOH?

pOH is a measure of [OH^-] concentration. Each increment on the pOH scale is by a factor of 10. For example, pOH from 11 to 12 is decreasing [OH^-] by a factor of 10. pOH from 11 to 13 is decreasing [OH^-] by a factor of 100.

pOH is a logarithmic scale so a pOH greater than 7 is acidic and pOH less than 7 is basic

What does pOH have to do with H₃O⁺ (hydronium ions)?

pOH is a measure of [OH^-], so if [OH^-] decreases, that means [H₃O⁺] is increasing, and vice versa. Since we said the increments on the pOH scale are by a factor of 10; going from 11 to 13 on the pOH scale is decreasing [OH^-] by a factor of 100.

Since [OH^-] is decreasing by a factor of 100, that means [H₃O⁺] is increasing by a factor of 100

H₃O⁺ and H⁺ are exactly the same, just written in different ways.