HardChemistryHigh School (11–12)Organic Compounds with Functional Groups › Alcohols, Phenols and EthersNumerical
A student oxidises 4.60 g of ethanol. In one experiment the ethanal is distilled out as it forms…
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A student oxidises of ethanol. In one experiment the ethanal is distilled out as it forms, so three ethanol use one dichromate. In a second experiment the mixture is heated under reflux until the acid forms, so three ethanol use two dichromate. Use for ethanol and for potassium dichromate. Find the least mass of potassium dichromate for each experiment.
Need a reminder? The key ideaShow
Dichromate takes 6 electrons. Ethanol to ethanal: 3 ethanol per dichromate. To ethanoic acid: 3 ethanol per 2 dichromate. products. Atom economy . NaBH reduces C=O of aldehydes and ketones. LiAlH also reduces esters and acids.
The worked solution
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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.
Given. of ethanol.
Step 1. Ethanol. .
Step 2. Ethanal. of dichromate. Mass: .
Step 3. Ethanoic acid. Twice as much dichromate: . Mass: .
Check. The acid needs two electrons more for each ethanol, so it needs exactly twice the dichromate.
Answer: and .
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