Explanation:
Benzene molecule is a made up of six carbon atoms and six hydrogen atoms.It molecular formula is given by [tex]C_6H_6[/tex]
In aldehyde functional group , (-CHO), in whicgh oxygen s double bonded to carbon and hydrogen is bonded to carbon as well. This functional group is forms bond via carbon atom with carbon atom of another organic molecule.
So, when aldehyde group replaces the single hydrgen atom of benzene molecule , it becomes [tex]C_6H_5CHO[/tex] that is benzaldehyde.
The structure is given in an image.