Question

Bromination of acetanilide and 4-methylacetanilide

1.) How do you perform limiting reactant, theoretical yield, and percent yield calculations involving multiple reaction steps

2.) What is the advantage of recrystallizing your product from a 1:1 aqueous ethanol solution rather than using ethanol alone?

KBro3 + 6HBr = 3H20 + 3Br2 + KBr

calculate limiting reactant, theoretical yield and percent yield? i used 0.265g of 1.8mmol of 4-methylacetanilide and added 0.110g of potassium bromate and 0.45ml of hydrobromic acid

Answer 1

1.) Write the equations for each step. Cross out intermediates until you get the net chemical equation. Compute the number of moles for each reactant, then compute for the theoretical yield assuming that all moles of limiting reactant are consumed. Remember that theoretical yield is the amount of product produced assuming all moles limiting reactant are consumed, and percent yield is the ratio of actual yield produced versus theoretical yield.

2.) Ethanol is a slightly non-polar compound due to its ethyl component and can dissolve both polar and non-polar compounds. The addition of water (a polar compound) would increase separation of your product (a non-polar compound) from the polar substances in the reaction, thus increasing yield.