(i) The functional group in CH3CHBr2 is bromine.
(ii) Since it has two C-atoms and 2-Br atoms, it should be named as dibromo ethane.
(iii) Both the bromine atoms are attached to the same C-atom and so the carbon chain should be numbered from the C-atom attaching bromine atoms. The structure of CH3CHBr2 is
Common name: Ethylidene dibromide.
IUPAC name: 1, 1 dibromo ethane.