"Nicotine in cigar smoke (pH 8.5) is much more readily absorped through the mucous membranes of the mouth than is nicotine in cigarette smoke (pH 5.3)..." [pKa for the pyridine NH (6-membered ring) is about 3, pyrrolidine NH pKa is about 8].
A. Use the Henderson-Hasselbalch and the definition of conjugate base/acid to determine the charge on most of the nicotine molecules or ions in the following pH ranges.
i. pH less than 3
ii. pH of 3 to 8
iii. pH of greater than 8
B. Use your answers in a. to explain the statement.