Hypobromous acid, HOBr, is a weak acid that dissociates in water, as represented by the equation
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
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
To calculate the value of [H+] in an HOBr solution with a pH of 4.95, we need to use the equation for pH:
pH = -log[H+]
Rearranging the equation, we get:
[H+] = 10^(-pH)
Substituting the given pH value of 4.95 into the equation:
[H+] = 10^(-4.95)
Calculating this using a calculator, we find:
[H+] ≈ 7.94 x 10^(-5) mol/L
Therefore, the value of [H+] in the HOBr solution with a pH of 4.95 is approximately 7.94 x 10^(-5) mol/L.