According to the Evans Pka Table, http://evans.rc.fas.harvard.edu/pdf/evans_pKa_table.pdf , the pKa of triphenylmethane is 31 and the pKa of diphenylmethane is 33. So there’s about a 100 fold increase in stability for the triphenylmethane conjugate base. Why do you think that is?
]]>The pKa of toluene is about 42. The pKa of ethyne is about 25. So the anion on the conjugate base of ethyne is much more stable than the anion in the conjugate base of toluene.
]]>It means it’s less concentrated; it’s spread out over a greater volume.
]]>Edit: Noticed that the lone pair on the carbon is localized so it can’t be stabilized through delocalization so never mind that last question :).
Thanks again.
Thank you, I think I am starting to get it. This is analogous to electronegativity since in both cases (higher sp character / electronegativity) the bond is pulled closer towards the nucleus.
Would it be right to say that the delocalization of the p orbitals between both atoms in CN(-) also plays a part in stabilizing the negative charge?