Homologous series A-level Chemistry

For the characteristics of homologous series 'Consecutive members of the series differ from each other by -CH2- group and their molecular weight differs by 14 units'- does this only applied to alkanes? Thank you

For the characteristics of homologous series 'Consecutive members of the series differ from each other by -CH2- group and their molecular weight differs by 14 units'- does this only applied to alkanes? Thank you

The OCR definition we learnt was "a series of molecules with the same functional group where each member differs by -CH2". I think you can ignore the 14 units thing. And no, a homologous series can also be with alkenes, anything that fits the definition (in alkenes the C=C is the functional group). As long as all the members have the same functional group and increase/decrease by a -CH2 then it's a homologous series.

No.

Methanol is different from ethanol by the inclusion of an CH2 group and then propan-1-ol, butan-1-ol etc.
Methanal, ethanal, propanal...
Propanone, butanone...
Methanoic acid...
etc. etc.