芳香ほうこうぞく炭化たんか水素すいそであれば
hōkōzokutankasuisodeareba

Noun
Da Copula

The "-eba" conditional form ("if/when…") of 芳香族炭化水素

1. if it is an aromatic hydrocarbon; when it is an aromatic hydrocarbon

Ba Conditional