All the reactions `i)` to `(v)` are examples of:

Options

A. Wurtz reaction
B. Wurtz-Fitting reaction
C. UIImann reaction
D. Frankland reaction

Answer

`c`

Explanation

If a least three of the `2,2'.6`, and `6'` are occupied by sufficiently large groups, free rotation about the single bond joining the two phenyl each ring has no vertical plane of symmetry. This restricted rotation gives rise to optical acticity due to molecule being asymmetrical as a whole. Hence, `6-` nitrobiphenyl `-2, 2'` dicarboxylic acid `(a)` and `6.6'-` diamano `-2,2'` dimenthyl biphenyl `(b)` have resolaved. If the substituent groups are large enough. then only two groups in the `o-` and `o'-` position will cause restricted rotation , e.g. bipheny `1-2,2'` disulphotic acid `(c)` has been shown to be optically active.
So, `(a), (b)`, `(c)` are resolvable.
The cause of restricted rotation is mainly due to steric effects of the groups in the `o-` and `0'-` positons (not at `m` and `m', p` and `p'` ) this type of steroisomerism arising from restricted rotaion about a single bond and where the steroisomers can be isolated is called atropisomerism and the isomers are called attopisomers.
All examples are Ullmannn reaction.