Hi All,

I need some suggestions regarding Hammett Plot. Generally, we need ratio of reaction constant (kS/kH) to get a plot against Hammett substituent constant (sigma). Further, its gradient gives the reaction constant (rho).

i) How can we calculate reaction constant for a reaction (3M reactant) completing in 3 mins? (pseudo-first order) What are the differences among rate, overall rate and rate constant? Can we substitute reaction constant with reaction rate values (units are asimilar)?

ii) For the plot, if we don’t have unsubstituted reactant (H), what can be done/measured to replace kS/kH? Here, the data for other substituents can be measured.

Thanks in advance!

Keshab