Write the organic product of each reaction…
Contributed by StemPy LabTry it on paper first. A hint, the key idea and the worked solution are here when you need them.
Write the organic product of each reaction.
- butanal and NaBH, then dilute acid
- butanone and LiAlH, then dilute acid
- propanone with Zn-Hg and concentrated HCl
- benzaldehyde with hydrazine, then KOH in ethylene glycol at 473 K
- cyclohexanone with H over nickel
Need a reminder? The key ideaShow
NaBH, LiAlH and H with a metal reduce C=O to an alcohol. Zn-Hg with conc. HCl (Clemmensen) or NHNH then KOH (Wolff-Kishner) reduce it to CH. Tollens' reagent gives 2 Ag for each aldehyde group, and Fehling's solution gives 1 CuO. The iodoform test is given by CHCO- groups and CHCH(OH)- groups.
The worked solution
Have you tried it?
Work it out on paper first. It is fine to get stuck or make a mistake: that is how we learn. When you are ready, go through the solution one step at a time, and check each step against your own.
Step 1. An aldehyde gives a primary alcohol: butan-1-ol.
Step 2. A ketone gives a secondary alcohol: butan-2-ol.
Step 3. Clemmensen turns C=O into CH: propane.
Step 4. Wolff-Kishner also turns C=O into CH: toluene (methylbenzene), with nitrogen gas as the by-product.
Step 5. Catalytic hydrogenation: cyclohexanol.
Check. Steps 3 and 4 remove the oxygen. Steps 1, 2 and 5 keep it as an O-H group.
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