Edexcel IAL Chemistry A2 11.12 Iodination and iodine clock practicals
Edexcel IAL Chemistry A2 11.12 Iodination and iodine clock practicals
Stop the sampled reaction without introducing a second catalyst, state the blue-black starch endpoint and convert thiosulfate moles to iodine using the 2:1 ratio.
How this is tested
- Explain why hydrogencarbonate neutralises acid while NaOH would continue catalysis.
- State the starch–iodine endpoint as blue-black once thiosulfate is consumed.
- Calculate iodine amount from thiosulfate using the 2 mol to 1 mol stoichiometric ratio.