Question

Given pH = 8.55 Find: [H3O+] and [OH-] Is this acidic, basic or neutral?

Answer 1

Answer:

Explanation:

The given pH = 8.55

Unknown:

[H₃O⁺] = ?

[OH⁻] = ?

In order to find these unknowns we must first establish some relationship.

                      pH = -log[H₃O⁺]

                   8.55 = -log[H₃O⁺]

                    [H₃O⁺] = inverse log₁₀(-8.55) = 2.82 x 10⁻⁹moldm⁻³

To find the [OH⁻],

                     pH + pOH = 14

                               pOH = 14 - pH = 14 - 8.55

                                pOH = 5.45

              pOH = -log[OH⁻]

               [OH⁻] = inverse log₁₀ (-5.45) = 3.55 x 10⁻⁶moldm⁻³

The solution is basic because it has more concentration of OH⁻ ions compared to H⁺ ions.