How many constitutional isomers exist for formula `C_(5)H_(12)O` that contain an ether as a functional group.

The number of constitutional isomers of the formula C_(5)H_(11) Br is

How many structrual isomerse exist for C_(7)H_(8)O where each isomer contain a phenyl ring?

The total number of constitutional isomers with the molecular formula C_(5)H_(11)Cl is

How many isomeric amines with the formula C_(7)H_(9)N contain a benzene ring and also primary amine functional group?