Codeine 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. The formula of codeine is \(\mathrm{C}_{18} \mathrm{H}_{21} \mathrm{NO}_{3}\) and the \(\mathrm{p} K_{\mathrm{b}}\) is 6.05 . Calculate the \(\mathrm{pH}\) of a \(10.0-\mathrm{mL}\) solution containing \(5.0 \mathrm{mg}\) of codeine \(\left(\mathrm{p} K_{\mathrm{b}}=-\log K_{\mathrm{b}}ight)\).