Flashcards
Oxidising Alcohols
Cards in this deck (20)
- 1What colour does ethanol burn with?Pale blue flame
- 2What happens to ethanol when it is burnt in oxygen?The C-C and C-H bonds are broken as the ethanol is completely oxidised to make CO₂ and H₂O
- 3Give the balanced symbol equation for the combustion of ethanol.C₂H₅OH + 3O₂ --> 2CO₂ + 3H₂O
- 4Apart from burning, what is another way of oxidising alcohols?Use the oxidising agent acidified potassium dichromate (VI) (K₂Cr₂O₇/H₂SO₄)
- 5What happens to the acidified potassium dichromate (VI) during an oxidation reaction?The orange dichromate (VI) ion (Cr₂O₇²⁻) is reduced to the green chromium (III) ion (Cr³⁺)
- 6Complete the sentences: A primary alcohol is first oxidised to an ______________. This _______________ can then be oxidised to a ______________ ______.A primary alcohol is first oxidised to an ALDEHYDE. This ALDEHYDE can then be oxidised to a CARBOXYLIC ACID.
- 7What does the notation [O] represent?An oxidising agent
- 8Describe the method of oxidising primary alcohols to aldehydes, including the reactantsGently heat the primary alcohol with potassium dichromate (VI) solution and sulfuric acid. The vaporised product will be distilled in a liebig condenser
- 9During the oxidation of ethanol to an aldehyde, how do you know that the product is ethanal?The product smells like apples
- 10Give the equation for the oxidation of ethol into ethanal, showing the displayed formula of the reactants and products
- 11Describe the method of oxidising primary alcohols to carboxylic acidsThe alcohol is mixed with excess oxidising agent and vigorously heated under reflux.
- 12During the oxidation of ethanol to a carboxylic acid, how do you know that the product is ethanoic acid?The product smells like vinegar
- 13Why is it important to oxidise an alcohol under reflux (primary alcohol --> carboxylic acid)Heating under reflux means you can increase the temperature of an organic reaction to boiling without losing volatile solvents, reactants or products. Any vaporised compounds are cooled, condense and drip back into the reaction mixture
- 14Give the equation for the oxidation of ethol into ethanoic acid, showing the displayed formula of the reactants and products
- 15What is the product of oxidising a secondary alcohol with acidified dichromate (VI)?Ketone
- 16TRUE OR FALSE: Ketones can be oxidised further by refluxFALSE
Ketones can't be oxidised easily, so even prolonged refluxing won't produce anything more - 17Give the equation for the oxidation of propan-2-ol into propanone, showing the displayed formula of the reactants and products
- 18What is the product of oxidising a secondary alcohol with acidified dichromate (VI)?Nothing - tertiary alcohols don't react with acidified potassium dichromate (VI) at all.
- 19What is the only way to oxidise tertiary alcohols?By burning them
- 20How can you distinguish tertiary alcohols from primary and secondary alcohols?Heat a sample of an unknown alcohol in a test tube with a few drops of orange potassium dichromate (VI) and a few drops of concentrated sulfuric acid.
If the alcohol is...
Tertiary = solution stays orange
Secondary/primary = orange --> green (as alcohol is oxidised and orange dichromate (VI) ions are reduced to green chromium (III) ions)
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- User has deleted their subject information Flashcards on Oxidising Alcohols, created by Deleted user on 12/03/2018.
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- Deleted user · Mar 2018
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- Mar 12, 2018
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- Created by Yinka F · Mar 8, 2018
- Copied by Yinka F · Mar 12, 2018
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