Deuterium oxide(D20, where D is deuterium, the hydrugen-2 isotope) has an ion product constant, Kw, of 8.9 x 10^-16 at 20 degrees celsius. Calculate [D+] and [OD]- for pure(neutral) D2O at this temperature.
wow, i would not have guessed its K is so far from H2O’s K
[D+] [OD-] = 8.9 e-16
take the square root
[D+] = [OD-] = 2.98 e-8
your answer: [D+] = [OD-] = 3.0 e-8
p.s. it has a “pD” of 7.5