Question

When dissolved in water, hydrogen bromide (hbr) forms hydrobromic acid. determine the hydroxide ion concentration in a 4,500 ml solution containing 3.78 g hydrogen bromide; kw = 1.00 × 10¯14?

Answer 1

No of moles of HBr = 3.78g / 80.9 = 0.0467moles
Molarity = Number of moles/ volume. So we have 0.0467 / 4.5 = 0.0103M.
Kw = 1.0 x 10 -14 = [H3O+] [OH-] and [OH-] = 1.0 x 10^(-14) / [H3O+]
So [OH-] = 1.0 * 10^(-14) /1.03 *10^(-2) = 0.9703 * 10^(-12) M