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Explin about inductive effect. (ii) What do you mean by conformation ? Explain about staggered conformation in ethane . |
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Answer» Solution :It is defined as the change in the polarization of a covalent bond due to the presence of adjacen bonded atoms or groups in the molecule. It is denoted as I-effect . <BR> 2 . Atoms or groups which lose ELECTRON towards a carbon atom are said to have a + I effect. Example `CH_(3)-,(CH_3)_2 CH-,(CH_3)_2C` etc . 3 Atoms or groups which draw electrons AWAY from a carbon atom are said to have a- I effect. Example , `-NO_(2),-I,-Br,-OH,C_6H_5` etc. For example, consider ethane and ethyl chloride. The C-C bond in ethane is non- polar while the C-C bond in ethyl chloride is polar. We know that chlorine is more electronegative than carbon and hence it attracts the shared pair of electrons between C-Cl in ethyl chloride towards itself. `overset(deltadelta^+)underset(2)CH_(3)rarr-overset(delta)underset(1)CH_(2)rarr-overset(delta)Cl` This develops a slight negative charge on chlorine and a slight positive charge on carbon to which chlorine is attached. To compensate it, the `C_1` draws the shared pair of electron between itself and `C_2`. This polarization effect is called inductive effect. (ii) The rotation about C-Csingle bondaxis yielding several ARRANGEMENTS of a hydrocarbon called conformers. Staggered conformation: In this conformation, the hydrogens of both the carbon atoms are FAR apart from each other. The repulsion between the atoms is minimum and it is the most stable conformer. 
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