Aldehydes and ketones (A-level only)

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Question 5
Medium

Aqueous NaBH4\text{NaBH}_4NaBH4​ reduces aldehydes but does not reduce alkenes.

1.

Show the first step of the mechanism of the reaction between NaBH4\text{NaBH}_4NaBH4​ and 3-methylbutanal. You should include two curly arrows.

[3]
2.

Explain why NaBH4\text{NaBH}_4NaBH4​ reduces 3-methylbutanal but has no reaction with 3-methylbut-1-ene.

[2]
3.

A student attempted to reduce a sample of 3-methylbutanal but added insufficient NaBH4\text{NaBH}_4NaBH4​. The student confirmed that the reduction was incomplete by using a chemical test.

Give the reagent and observation for the chemical test.

[2]

Aldehydes and ketones (A-level only) Questions

  1. A Level
  2. /Chemistry
  3. /Aldehydes and ketones (A-level only)