Codeine (C18H21NO3) is a derivative of morphine that is used as an analgesic, narcotic, or antitussive. It was once commonly used in cough syrups but is now available only by prescription because of its addictive properties. A solution of codeine is made by dissolving 7.79 g of codeine in water to make 14.7 L of solution. If the pH of this codeine solution is 9.59, calculate the Kb of codeine.