Explain why the following names are incorrect? ,
(i) `3, 4, 7`- Trimethylbutyl)-`3`-ethyldecane
(ii) `5-(2,2`-Dimenthylvutyl)-`3`-ethyldecane
(iii) `5`-Ethyl-`3`-methylheptane
Strategy: First write down the structure of the alkane according to the given name. Then rename it according to the prescribed `IUPAC` rules. Any mismatch will help to identify the error.

Explanation

(i)
The new set of locants `(2,5,6)` is lower than the old set of locants `(3,4,7)` according to the principle of first point of difference.
(ii)
Greater number of substitutents should be attached to the parent chain. In the incorrect name, the parent chain carries only two side chains.
(iii)
If two different substituents are in identical position from either side, then lower number is given to that substituent which comes first in the name according to the alphabetical order.