Bromoethane, C2H5Br\text{C}_2\text{H}_5\text{Br}C2H5Br, can be prepared by several different chemical pathways. Which reaction has the lowest atom economy for the production of bromoethane?
(Relative atomic masses: H=1.0\text{H} = 1.0H=1.0, C=12.0\text{C} = 12.0C=12.0, O=16.0\text{O} = 16.0O=16.0, Na=23.0\text{Na} = 23.0Na=23.0, S=32.1\text{S} = 32.1S=32.1, Br=79.9\text{Br} = 79.9Br=79.9)
C2H5OH+HBr→C2H5Br+H2O\text{C}_2\text{H}_5\text{OH} + \text{HBr} \rightarrow \text{C}_2\text{H}_5\text{Br} + \text{H}_2\text{O}C2H5OH+HBr→C2H5Br+H2O
C2H5OH+NaBr+H2SO4→C2H5Br+NaHSO4+H2O\text{C}_2\text{H}_5\text{OH} + \text{NaBr} + \text{H}_2\text{SO}_4 \rightarrow \text{C}_2\text{H}_5\text{Br} + \text{NaHSO}_4 + \text{H}_2\text{O}C2H5OH+NaBr+H2SO4→C2H5Br+NaHSO4+H2O
C2H4+HBr→C2H5Br\text{C}_2\text{H}_4 + \text{HBr} \rightarrow \text{C}_2\text{H}_5\text{Br}C2H4+HBr→C2H5Br
C2H6+Br2→C2H5Br+HBr\text{C}_2\text{H}_6 + \text{Br}_2 \rightarrow \text{C}_2\text{H}_5\text{Br} + \text{HBr}C2H6+Br2→C2H5Br+HBr
