CH4 - Aldehydes and Ketones - Flashcards in A Level and IB Chemistry

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Created by: Tashaleese_99
Created on: 05-12-16 19:59

What happens when you add Tollen's reagent to an aldehyde and a ketone?

Aldehyde = grey precipitate/silver mirror. Ketone = no effect. The aldehyde is oxidised into a carboxylic acid.

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What happens when you add Fehling's reagent to an aldehyde and a ketone?

Aldehyde = orange/red ppt. Ketone = the solution remains blue. The aldehyde is oxidised to form a carboxylic acid.

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Nucleophilic addition of CN- to aldehydes and ketones - conditions?

NaCN or KCN

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What happens to an aldehyde and/or ketone when they react with 2, 4 DNP and what does this allow?

They become solids (an orange/red ppt is formed). This is filtered off and purified to form a HYDRAZONE. The melting point of this product is then compared with a table of known values to identify the exact aldehyde/ketone.

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Brady's reagent - conditions and mechanism?

Conditions: concentrated sulphuric and nitric acid, 50'C and reflux. Mechanism: nucleophilic addition elimination.

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What does the iodoform test indicate the presence of?

CH3CO group - a yellow ppt forms if this group is present.

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Iodoform test - conditions?

NaOH solution of iodine and potassium iodide.

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State some common compounds that undergo the iodoform test.

Ethanal, ethanol and any alcohols with the OH group in the secondary position.

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Other cards in this set

Card 2

Front

What happens when you add Fehling's reagent to an aldehyde and a ketone?

Back

Aldehyde = orange/red ppt. Ketone = the solution remains blue. The aldehyde is oxidised to form a carboxylic acid.

Card 3

Front

Nucleophilic addition of CN- to aldehydes and ketones - conditions?

Back

Card 4

Front

What happens to an aldehyde and/or ketone when they react with 2, 4 DNP and what does this allow?

Back

Card 5

Front

Brady's reagent - conditions and mechanism?

Back

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CH4 - Aldehydes and Ketones