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Give the requirements for formation of pi bonds and explain active centre |
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Answer» <P> Solution :In a `pi` (pi) bond formation parallel orientation of the two p-ORBITALS on adjacent atoms is necessary for a proper SIDEWAYS overlap EG. For the formation of `pi` bond in `H_(2)C= CH_(2)`.All the atoms must be in the same plane. The p orbitals are mutually parallel. Both the p orbitals are perpendicular to the pane of the molecule. Effect on rotation on C-C bond: In `CH_(2)= CH_(2)`, the rotation of one `CH_(2)` fragment with respect to other interferes with maximum overlap of p orbitals and , therefore, such rotation about carbon-carbon DOUBLE bond (C = C) is restricted. Availability of electron by `pi` bond and reactive centres of reactions: The electron charge cloud of the `pi` bond is located above and below the plane of bonding atoms. This results in the electrons being easily available to the attacking reagents. In general `pi` bonds provide the most reactive centres in the molecules containing multiple bonds |
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