## General Chemistry: Principles and Modern Applications (10th Edition)

$C_{18}H_{21}O_3NH^+(aq) + H_2O(l)$ $C_{18}H_{21}O_3N(aq) + H_3O^+(aq)$ $pKb = 7.95$
1. Write a reaction where protonated codeine acts like an acid: $C_{18}H_{21}O_3NH^+(aq) + H_2O(l)$ $C_{18}H_{21}O_3N(aq) + H_3O^+(aq)$ ** It needs to be donating one proton. 2. As we can see, codeine and protonated codeine are a conjugate acid-base pair, therefore: $pKa + pKb = pKw = 14$ $6.05 + pKb = 14$ $pKb = 7.95$