eng Science and Education Publishing World Journal of Chemical Education 2375-1657 2020-09-27 8 4 155 162 10.12691/wjce-8-4-3 WJCE2020843 article R. Sanjeev 1 V. Jagannadham jagannadham1950@yahoo.com 2 Department of Chemistry, Geethanjali College of Engineering and Technology Cheeryal-501301, Telangana, India Department of Chemistry, Osmania University, Hyderabad-500007, India Collection of interesting and stimulative data led us to construct Hammett plots for different properties like proton affinities, gas phase basicities, solvation free energies of free and protonated benzenes (I), pyridines (II) and phosphorines (III), and for pKa values of protonated pyridines and phosphorines. Trends in Hammett reaction constants () for all these processes were discussed. http://pubs.sciepub.com/wjce/8/4/3/wjce-8-4-3.pdf benzenes pyridines phosphorines pK_a proton affinities gas phase basicities solvation free energies