Question

the atom economy as calculated for an elimination reaction was 20% but the reaction mass efficiency was only 15%. Why do you think there is a discrepancy between the two? Which number is more reliable?

Answer 1

As the atom economy is only 20%( low), though we get reaction mass efficiency - 15% is not bad at all. As the atom economy is the molar masses ratio of products /reactants, thus for an elimination reaction it is low means that, elimination wasn't done at such extent theortically, as the atom economy is called as theoretical yield. It means that out of only 20% theortical yield we got 15 % reaction mass efficiency= mass obtained of products / mass obtained of reactants ( observed yield ), is good. The reason between the discrepancy between these two maybe due to some personal errors while doing elimination or it can be due to experimental error. According to me there's more chances of happening personal error like as in measuring the amount of reactants or as just we use apparatus that were not accurate in their measurement as the measuring cylinder /beakers have approximate volume measurement. Because of such reasons, this shows discrepancy, in other words the reaction can't go exactly upto its extent (20%). According to me the 15% (reaction mass efficiency) is more reliable because as theoretically we had got only 20%( reaction mass efficiency) out of which we got 15%( reaction mass efficiency) which is not bad at all. So the 15% is more reliable