Distillation of a product from a reaction - part 3

Question 1

WHy must the liquid need to be dried

Answer 1

may contain water

Question 2

How is it dried?

Answer 2

• adding drying agent
  
  • e.g. anhydrous calcium chloride
• swirl
• add more drying agent until all the liquid changes from cloidly to clear
• filter or decrant of the liquid into a clean, dry flask

Question 3

How are impurities detected?

Answer 3

• if the boiling point is sharp, it is pure, if it covers a range then impurities may be present
• if the boiling point recorded during distillation is the same as in data books, the correct product has been obtained

Question 4

What are the theoretical reasons for the yield being less than 100%

Answer 4

• side reactions
• impure reagents
• incomplete reaction

Question 5

What are the practical reasons for the yield being less than 100%

Answer 5

• some product lost in the purification steps
• lost in distillation