Three reagents are added separately to four organic compounds - AQA - A-Level Chemistry - Question 23 - 2019 - Paper 3
Question 23
Three reagents are added separately to four organic compounds.
Which row shows the correct observations?
Sodium hydrogen carbonate Acidified potassium dichromate(V... show full transcript
Worked Solution & Example Answer:Three reagents are added separately to four organic compounds - AQA - A-Level Chemistry - Question 23 - 2019 - Paper 3
Step 1
Sodium hydrogen carbonate - Effervescence
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Answer
Effervescence is observed when sodium hydrogen carbonate reacts with carboxylic acids. Therefore, both Propan-1-ol and Propanoic acid will show effervescence.
Step 2
Acidified potassium dichromate(VI) - Orange solution turns green
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Answer
Only aldehydes are oxidized by acidified potassium dichromate(VI). Propanal will turn the solution green as it is an aldehyde while propanone, being a ketone, will not change the color.
Step 3
Tollens' reagent - Silver mirror
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Answer
The Tollens' reagent will give a silver mirror only with aldehydes. Propanal will produce a silver mirror while propanone will not.
