Why is water added after the reduction process of aldehyde and ketone with LiAlH4?
Correct answer: A. Because water reacts violently with LiAlH4
- A. Because water reacts violently with LiAlH4
- B. Because water will protonate LiAlH4
- C. Because water inhibits the process
- D. Because it will result to alkenes
Explanation
This is the correct option. LiAlH₄ is a highly reactive reducing agent. When water is added to a reaction mixture containing LiAlH₄, it reacts vigorously, leading to the release of hydrogen gas and the formation of aluminum hydroxide. Therefore, water is typically added after the reduction to safely quench the reaction and convert the reaction intermediates into alcohols.
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About Reactivity of Aldehydes and Ketones
The polar carbonyl group makes aldehydes and ketones undergo nucleophilic addition, reduction and condensation reactions. Aldehydes are generally more reactive and oxidise readily to carboxylic acids, whereas ketones resist mild oxidation; reactions with hydrogen cyanide, sodium bisulfite and 2,4-DNP help identify their behaviour.
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