Question

Rank the following groups of monomers from most able to least able to undergo anionic polymerization:

Short answer

Electron withdrawing groups withdraw electrons from the ring and there by increase the stability of carbanion and thereby it undergoes anionic polymerization.

Step-by-step solution

Order of monomers (a)

NO₂ groups are good at electron withdrawal so that, carbanion formed triggers the alkene to be most reactive towards anion polymerization.The ease of formation of carbanion is high for electron withdrawing groups.

Order of monomers (b)

Cyanide group is the most electron withdrawing group compared to chlorine and alkyl group. Thus, the order of formation of carbanion is decreasing from cyanide>chlorine>alkyl.This in turn decrease the ability towards anionic polymerization.

Thus, the order of monomers from most able to least able to undergo anionic polymerization is explained above