6092 Oxidising and Reducing Agents post practical discussion

Reagent A is a blue substance. How did this affect the use of potassium iodide as test reagent in steps for testing for oxidising agents?

Answer explanation

A positive potassium iodide test should result in a yellow colour, but the blue substance caused a green colour to be observed instead.

From your observation in step (e) in test for oxidising agent, suggest what this might imply about the role of potassium iodide in this reaction.

From your observation in step (e) in test for oxidising agent, suggest whether this reaction is a redox reaction. Explain your answer.

Answer explanation

The reaction is a redox reaction as KI solution turn yellow.

Testing for oxidising agents with potassium iodide may be complicated by the behaviour of the iodide ion. Silver nitrate is known to be an oxidising agent. Why would the use of potassium iodide be complicated when added to silver nitrate?

Answer explanation

silver iodide would be precipitated as yellow solid, a positive test (yellow solution) would be hard to observed.

Copper(II) salts tend to appear blue, but copper(I) salts may appear white or grey. Based on your observation, suggest whether the precipitate is likely to be copper(I) iodide or copper(II) iodide.

Which of the reagents A to E are oxidising agents?

• A

• B

• C

• D

• E

Which of the reagents A to E are reducing agents?

• A

• B

• C

• D

• E

Describe any challenge(s) you have encountered in this experiment and suggest how they can be overcome.

Describe 3 key learning points you have learned from today's lesson.

List and state any questions that you have on today's lesson.