13A - Iodine-Propanone Reaction

Question 1

Describe the method for the continuous monitoring method of the reaction of Propanone + Iodine

Answer 1

1- Add aqueous Propanone + Sulphuric Acid
2- Add Iodine solution + start stop clock
3- use pipette to take samples at regular intervals
4- Add Sodium Hydrogen Carbonate to stop reaction of sample taken
5- Titrate remaining Iodine remaining with Sodium Thiosulfate + Use Starch Indicator to determine end point
6- continue this method until you have a table of results

Question 2

What is happening in core prac 13a between Propanone + Sulphuric acid + Iodine

Answer 2

Sulphuric acid protonates/reacts with Propanone via electrophilic addition = Attacks C=O bond

Eventually Iodoalkane forms = less iodine in solution as reaction goes on

Thioslufate reduces Iodine to Iodide so can determine how much Iodine is less in solution with Starch indicator

Question 3

Role of Sodium Thiosulfate - 13a

Answer 3

Thiosulfate reduces iodine to iodide in titration

Question 4

Diagram of what’s going on in CP13a - Propanone + Sulphuric acid

Answer 4