Answer to Question #345838 in General Chemistry for Meg

Question

What is the pH of a 1.5x10^-3 M solution of NaOH, a strong base? Show your work.

Answer 1

1.

First we find pOH . pOH is the negative of the logarithm of the OH^– ion concentration:

pOH = - log [OH^–].

Since NaOH => Na⁺ + OH^– , the OH^– concentration is equal to the NaOH concentration. That is 1,5*10^–3 mol/l

pOH is the negative of the logarithm of the OH^– ion concentration.

pOH = - log [OH^–] = -log (1,5 * 10^–3) =

= 3 - log (1,5) = 3 - 0,176 = 2,824

2.

Knowing that the sum of pH and pOH in the solution is 14, we find the pH :

pH = 14 – pOH = 14 – 2,824 = 11,176

ANSWER: pH = 11,176