Imines are similar to carbonyls, but with the oxygen atom replaced by a nitrogen atom:

a$.$ Use a molecular orbital diagram to predict whether imines would be more reactive or less

reactive towards nucleophiles than carbonyl compounds under basic conditions.

b$.$ Suppose the $p{K}_a$ of a protonated imine is $7\mathrm{.}0.$ What percentage of the imines would be

protonated at the following $pH$ values?

$p{K}_a=7\mathrm{.}0$

pH $11$

pH $9$

pH $8$

pH $7$

pH $6$

pH $5$

$pH3$