Final answer:
The Kb for oxycodone, a weak base, is approximately 6.25 x 10^-9 M.
Step-by-step explanation:
Oxycodone, a weak base, can undergo ionization in water to form hydroxide ions (OH-) and its conjugate acid. The concentration of hydroxide ions in a 0.140 M solution of oxycodone is equal to 3.65 x 10-6 M. To calculate Kb, which represents the strength of a weak base, we can use the equation Kb = Kw / Ka, where Kw is the ion product of water (1.0 x 10-14) and Ka is the second ionization constant (1.6 x 10-4). By substituting the values, we can find that the Kb for oxycodone is approximately 6.25 x 10-9 M.