JEE Advanced levelSingle correct optionDifficulty 3 of 3ev210
Ethanol is made by two routes. Route A: CX2HX5Br+NaOHCX2HX5OH+NaBr, yield 90%. Route B: CX2HX4+HX2OCX2HX5OH, yield 60%. Use atomic masses H 1, C 12, O 16, Na 23, Br 80. Which statement is correct?
ARoute B has the higher atom economy, but route A gives more ethanol per mole of limiting reactant
BRoute A has the higher atom economy and gives more ethanol per mole of limiting reactant
CRoute B has the higher atom economy and also gives more ethanol per mole of limiting reactant
DRoute A has the higher atom economy, but route B gives more ethanol per mole of limiting reactant
Answer: A
Atom economy of A =46/(109+40)=30.87% and of B =46/(28+18)=100%, so B is higher. Yield is separate: per mole of limiting reactant, A gives 0.90 mol and B gives 0.60 mol ethanol. So atom economy and yield point in opposite directions.