Question

alkanes and cycloalkanes have the same general formula but they are not homologues why

Answer 1

Alkanes and cycloalkanes do not have a same general formula.
Alkane = CnH2n+2
Cycloalkane = CnH2n
Only alkenes and cycloalkanes have the same general formula.
Homologous series doesn't just have the same general formula.
They also have the same functional group.
So, in case of alkenes, the functional group is the double bond whereas, in case of cycloalkanes, the functional group is the carbon ring.
As the two have different functional groups, they are not homologous despite having the same general formula.

I hope it helps u