So, we were shown a Hammett plot that, on the left was linear, but on the right was concave up. How would I explain the shape of the Hammett plot? Does it depend on whether the substituent is an EDG or an EWG? Is it based on the mechanism of the reaction/rds?
Also, a hypothetical question was proposed to us regarding the generation of Hammett plots: how would you generate a Hammet plot for a ring with multiple substituents? The sigma value, sigma+ value, etc. are based on a single substituent, right? So, if you were to have multiple substituents, then what would you do? Would the plot be 3D with two axes for sigma or would you just compare the groups and see which one has the larger effect?