Question

Given [OH-] = 5.5 x 10-10M Find: [H3O+] and pH Is this acidic, basic or neutral?

Answer 1

Answer:

Explanation:

Given parameters:

Hydroxide ion concentration = 5.5 x 10⁻¹⁰M

Unknown:

concentration of hydroxonium ion [H₃O⁺]= ?

pH = ?

Solution

To determine the concentration of the hydroxonium ion, we know that from the ionic product of water:

                        [H₃O⁺][OH⁻]= 10⁻¹⁴

                        [H₃O⁺] = $\frac{10^{-14} }{OH^{-} }$

                        [H₃O⁺] = $\frac{10^{-14} }{5.5 x 10^{-10} }$

                        [H₃O⁺] = 1.8 x 10⁻⁵M

To find the pH of the solution, we use the expression below:

                  pH = -log₁₀[H₃O⁺]

                 pH = -log₁₀ 1.8 x 10⁻⁵ = -(-4.74) = 4.7

Since the pH of the solution is 4.7, it is acidic.