Which is more acidic, an sp2 C-H proton, or an sp C-H proton, and why?
The sp H is more acidic because in an sp hybrid, electrons are generally held closer to the nucleus due to more s character in the hybrid. Thus, the proton is removed more easily.
What is the 18 electron rule?
This rule generally applies to organometallic compounds, in particular Fe, Cr, Mn, and Co. Essentially, it parallels the 8 electron rule for rows 1-3 of the periodic table. If a metal has 18 electrons in its valence shell, it has achieved a noble gas configuration.
For any given acid HA with a known dissociation constant Ka, when does the ratio of H(+) to A(-) =1?
When pH = pKa