Question

Arrange the following monomers in order of decreasing ability to undergo cationic polymerisation.

I. CH₂=CH -C₆H₄(NO₂)

II. CH₂=CH -C₆H₄(CH₃)

III.  CH₂=CH -C₆H₄(OCH₃)

(a) I > II > III

(b) II > I > III

(c) III > II > I

(d) I > III > II

Answer 1

The correct option is: (c) III > II > I

Explanation:

Electron releasing groups such as -CH₃, -OCH₃ activate the monomer towards cationic polymerisation because these groups provide stability to the carbocation formed. On the other hand, -NO₂ is a electron withdrawing group. So, it reduces the stability of carbocation formed. Thus, the correct order is