Question

What was the balanced ionic equation for the reaction of sodium bisulfite with bromine?

(write out 2 half equations that needed to balance the reaction)

Procedure: Lab bromination of acetanilide

0.679g of acetanilide in 2.5 mL of glacial acetic acid. Add 0.25 mL bromine. Allow the mixture to stand for 10 minutes. Pour into 30 mL of ice water and rinse out the flask with a few more mL of ice water. Slowly add dropwise a sodium bisulfite solution, until excess bromine has gone. Filter, wash with water and allow vacuuming for a few extra minutes to dry. Recrystallize from ethyl alcohol. Measure the weight and the melting point.

Product recrystallized was 0.87g.

If possible can someone give me the steps of finding the %yield? is it 0.679/0.87 x100%?

Answer 1

molar mass of acetanilide = 135 g/mol

  molar mass of 4-bromo acetanilide = 214 g/mol   

acetanilide + Br₂ ---------------> 4-bromo acetanilide

135 g 214 g

0.679 g ?

  

? = ( 0.679 g/ 135 g) x 214 g of  4-bromo acetanilide

= 1.076 g of 4-bromo acetanilide

This is called theoretical yield of 4-bromo acetanilide.

Given that actual yield of 4-bromo acetanilide = 0.87 g

Therefore,

   % yield = (actual yield /  theoretical yield) x 100

= ( 0.87 g / 1.076 g ) x 100

= 80.8 %

Therefore,

  % yield of product =  80.8 %