The zwitterionic form of carbonyls is often used to explain their electrophilicity. Draw the zwitterionic structure of NO⁺₂. Why is this such a great electrophile at the central nitrogen?

Which nucleophile would be more reactive in the solvent given?

(b)

For each pair, choose the more reactive nucleophile.

(a)

In contrast to the results of Assessment 13.18, when a secondary haloalkane is treated with sodium ethanethiolate, we predict formation of a thioether. How is this rationalized?

Between pyrrole and pyrrolidine, which nitrogen would be most nucleophilic? Why?

Would you expect the following bases to favor E1 or E2 elimination?

(c)

For each pair, choose the more reactive nucleophile.

(b)

Would you expect methoxide ion to be a better nucleophile if it is dissolved in CH₃OH or if it is dissolved in DMSO? Why?

Indicate which species in each pair gives a higher substitution-product-to-elimination-product ratio when it reacts with isopropyl bromide:

a. ethoxide ion or tert-butoxide ion