Mark the main chains in the compounds given below.

(i) The given compound is:

The numbering of main chain in the above compound is given by:-

The main chain has been chosen containing the largest number of carbon atoms and giving the substituent bearing carbon the lowest number.

(ii) The given compound is:

The numbering of main chain in the above compound is given by:-

The main chain has been chosen containing the largest number of carbon atoms and giving the substituent bearing carbon the lowest number. Here two ways of numbering are there as shown in the structures above but either way we get the same length of the main chain and position of the two substituents. Hence, any one of the way can be chosen for numbering the main chain.