CHEMICAL TEST ON CARBONYL COMPOUNDS

Question 1

describe how the presence of carbonyl groups can be detected

Answer 1

• using brandys reagent
• brandys reagent is 2,4-dinitrophenylhydrazine dissolved in methanol and sulfuric acid
• when brandys reagent is added to an aldehyde or ketone a yellow/orange precipitate is formed
• the precipitate called 2,4-dinitrophenylhydrazone derivative confirms the presence of carbonly function group however there is no precipitation with a carboxylic acid or ester
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Question 2

how can you distinguish between an aldehyde or a ketone