Hypobromous acid, HOBr, is a weak acid that dissociates in water, as represented by the equation

Question

below:
HOBr(aq) ↔ H+(aq) + OBr–(aq) Ka = 2.3  10–9
(a) Calculate the value of [H+] in an HOBr solution that has a pH of 4.95

Answer 1

pH = -log[H+], so [H+] = 10^(-pH)

[H+] = 10^(-4.95) = 7.94 x 10^(-5) M

(b) Calculate the concentration of OBr- in an HOBr solution that has a pH of 4.95.

Since HOBr is a weak acid that partially dissociates in water, we can assume that the concentration of OBr- is equal to the concentration of H+:

[OBr-] = [H+] = 7.94 x 10^(-5) M