Answer to Question #106760 in Chemistry for sogol

Question

What is the [H+] in 0.025 M NaOH?

Answer 1

Solution:

NaOH is a strong base. This means it completely dissociates into its ions.

NaOH = Na⁺ + OH^-

Therefore, the concentration of OH⁻ is 0.025M.

[OH^-] = 0.025.

1) Therefore, we can calculate the pOH:

pOH = −log([OH⁻]) = −log(0.025) = 1.602

Therefore, now we can calculate the pH:

pH = 14 − pOH = 14 − 1.602 = 12.398

Now we can calculate the concentration of H⁺:

pH = -log([H⁺]);

[H⁺] = 10^{- pH} = 10^-12.398 = 3.99*10^-13 = 4*10^-13

[H⁺] = 4*10^-13 M

or

2) pH + pOH = 14;

-log[H⁺] + (-log[OH^-]) = 14;

[H⁺] * [OH^-] = 10^-14;

[H⁺] = 10^-14 / [OH^-];

[H⁺] = 10^-14 / 0.025 = 4*10^-13

[H⁺] = 4*10^-13 M

Answer: 4*10^-13 M is the [H⁺] in 0.025 M NaOH.