question_answer

Give the decreasing order of reactivities of the following monomers towards anionic addition polymerisation.

I. \[\operatorname{Me}-CH=C{{H}_{2}}\]

II. \[\operatorname{Ph}\,-\,\,CH=C{{H}_{2}}\]

III. \[{{\operatorname{CH}}_{2}}=CH\,-CN\]

IV. \[{{\operatorname{CH}}_{2}} = CC{{l}_{2}}\]

V. \[{{\operatorname{CH}}_{2}} = C{{F}_{2}}\]

VI. \[{{F}_{2}}C=C{{F}_{\text{2}}}\]

The correct order is

A)  \[\operatorname{VI}>III>V>IV>II\]      

B)  \[\operatorname{VI}>V>III>IV>II>I\]

C)  \[\operatorname{VI}>IV>V>III>II>I\]

D)  \[\operatorname{VI}>V>IV>II>I>III\]

Correct Answer: A

Solution :

Anionic polymerisation is favoured by the presence of electron donating group {e.g.,-X, -COOR, -CN etc.). More the number of electron donating group, the more stable is the intermediate carbanion, and consequently more favoured is the stability of   is Therefore, the decreasing reactivity order towards anionic polymerisation is \[\left( VI > III > V > IV > II > I \right)\]