Question

In an aqueous solution at 25 °C, if [H3O+] = 2.5 x 104 M, then [OH-]
is:

Answer 1

Answer: Therefore, the concentration of hydroxide ions [OH-] in the given solution is 4.0 x 10⁻¹⁹M.

We know that In an aqueous solution Kw is the ionization constant of water.

Kw = [H3O⁺][OH⁻]

[OH⁻] =
`(Kw)/([H3O^+])`--------------------------------------(a)

Kw = ionization constant of water

[H3O⁺]= the concentration of hydronium ions

[OH⁻] = the concentration of hydroxide ions

Kw = 1x10⁻¹⁴M²-------------------(i)

[H3O⁺]= 2.5 x 10⁴M------------------(ii)

[OH⁻] = ?

NOW Putting values in (i) and (ii) in equation (a)

[OH⁻] =
`(1 X 10^-^1^4)/(2.5 X 10^4)`

[OH⁻] = 4.0 x 10⁻¹⁹M