Thank you very much for this response. I have too many questions to ask. But one more thing about the same name, whether" dimethyl" should be written first or "ethyl" should be written first, means 'd' of dimethyl should be considered for alphabetical order with 'e' of ethyl

Dear addeshpnde@gmail.com

Dimethyl group should be written first then ethyl group because the letter 'd' comes alphabetically first before 'e'.

If there were only methyl group and one ethyl group in such a case alphabetically letter 'e' of ethyl group will get first preference before letter 'm' of methyl group.

Regards

Topperlearning Team.