The maximum number of structural isomers of hexane is

The maximum number of structural isomers possible for the hydrocarbon having the molecular formula C_(4)H_(6) , is

Maximum number of structural isomers for a pentane with molecular formula C_(5)H_(12) is

What is the number of structural isomers of monohalogenated n butane?

Number of structural isomers for C_6 H_14 is: