ethane vs methane series

ethane and methane series both are nouns.

Word	Noun	Adjective	Verb	Adverb
ethane	Yes	No	No	No
methane series	Yes	No	No	No

As nouns, methane series is a hypernym of ethane; that is, methane series is a word with a broader meaning than ethane:

ethane: a colorless odorless alkane gas used as fuel
methane series: a series of non-aromatic saturated hydrocarbons with the general formula CnH(2n+2)

Other hypernyms of ethane include hydrocarbon, alkane, alkane series, paraffin, paraffin series.

ethane (noun)	methane series (noun)
a colorless odorless alkane gas used as fuel	a series of non-aromatic saturated hydrocarbons with the general formula CnH(2n+2)