Draw the structural isomers of pentane.

Of the isomeric hexanes, the isomer which can give two mono chlorinated compounds is 

The following compounds $1$and  $2$ with the identical molecular formula, but different structures are called;

Draw the structures of the isomers for bromobutane. 
 

What are the possible isomers of organic compound?

${\mathrm{C}}_4{\mathrm{H}}_{10}$

${\mathrm{C}}_5{\mathrm{H}}_{12}$

Draw all possible structural formulae of compounds from their molecular formula given: ${\mathrm{C}}_3{\mathrm{H}}_4$