The conjugate acids of four different amines have the following pKa values:
• ethylammonium ion, pKa=10.8
• isopropylammonium ion, pKa=11.2
• anilinium ion, pKa=4.6
• pyridinium ion, pKa=5.2
Which parent amine is the strongest base under standard aqueous conditions?
a) ethylamine (CH3CH2NH2)
b) aniline (C6H5NH2)
c) isopropylamine ((CH3)2CHNH2)
d) pyridine (C5H5N)