The correct sequence of reagents used in the preparation of 4-bromo-2-nitroethylbenzene from benzene is:

The target molecule is 4-bromo-2-nitroethylbenzene. This is a benzene ring with an ethyl group, a bromo substituent at position 4 (para to ethyl), and a nitro group at position 2 (ortho to ethyl).

We need to build this from benzene. The ethyl group is an activating ortho/para director, while both $$-NO_2$$ and $$-Br$$ are meta directors (nitro) and ortho/para director (Br) respectively. The key challenge is introducing the ethyl group. Direct Friedel-Crafts alkylation can give rearrangement, so we use Friedel-Crafts acylation followed by Clemmensen reduction.

The correct sequence in option (2) is: First, $$CH_3COCl/AlCl_3$$ performs Friedel-Crafts acylation to give acetophenone. Then $$Zn\text{-}Hg/HCl$$ (Clemmensen reduction) reduces the carbonyl to give ethylbenzene. Next, $$Br_2/AlBr_3$$ brominates the ring; since the ethyl group is ortho/para directing, bromine goes to the para position giving 4-bromoethylbenzene. Finally, $$HNO_3/H_2SO_4$$ nitrates the ring; both the ethyl group (ortho/para director) and bromine (ortho/para director) direct the incoming nitro group to position 2 (ortho to ethyl and meta to bromine), giving 4-bromo-2-nitroethylbenzene.

Therefore, the correct answer is option (2).