An aqueous solution at 25 c has a OH - concentration of. Calculate the concentration. Be sure your answer has the correct number of significant digits.

Full Question:

An aqueous solution at 25 C has a OH - concentration of 2.5x10-4M. Calculate the H3O + concentration. Be sure your answer has the correct number of significant digits.

Answer:

4*10-9M

Explanation:

From the question;

[OH-] = 2.5x10-4M

[H3O+] = ?

The relationship between both parameters is given as;

Kw = [H3O+] * [OH-]

where k self-ionization constant of water, Kw = 1*10-14, which has no units.

Upon solving for [H3O+];

[H3O+] = Kw / [OH-]

Kw = 1*10-14

[H3O+] = (1*10-14) / 2.5x10-4

[H3O+] = 0.4 * 10-10

[H3O+] = 4*10-9M