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    A common step in the purification of organic liquid products is shaking with water followed by separation using a separating funnel.Explain why this would not be appropriate for purifying ethanoic acid.
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    There is something you need to know about organic solvents in general.

    "What happens if you put some oil on water?"

    It floats as a different layer. It's because they're non-polar molecules and alkanes have no ability to form hydrogen bonds, so water's attraction to itself is much stronger than its attraction to oil.

    The water is better at dissolving the gunk (commonly described as a "universal solvent") so when shaken, the impurities stay in the water and you have a clean layer of organic compound.

    Ethanoic acid is a constituent part of something you put on your fish and chips - vinegar. It gives you a clue that carboxylic acids in general don't behave like normal organic solvents.

    It dissolves extremely well in water and doesn't separate out in layers, because it has an -OH group that can form hydrogen bonds with the adjacent water molecules. If you have an impure sample, it won't separate out into a layer of clean sample with gunk dissolved in water.

    I'm not sure how the mark scheme rubric wants it to be stated, but I'd imagine it's something like

    1. Ethanoic acid dissolves in water (due to h-bonding)
    2. Therefore it will not separate when shaken with water
    3. So impurities cannot be isolated (and removed) using a separating funnel
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    (Original post by Rather_Cynical)
    There is something you need to know about organic solvents in general.

    "What happens if you put some oil on water?"

    It floats as a different layer. It's because they're non-polar molecules and alkanes have no ability to form hydrogen bonds, so water's attraction to itself is much stronger than its attraction to oil.

    The water is better at dissolving the gunk (commonly described as a "universal solvent" so when shaken, the impurities stay in the water and you have a clean layer of organic compound.

    Ethanoic acid is a constituent part of something you put on your fish and chips - vinegar. It gives you a clue that carboxylic acids in general don't behave like normal organic solvents.

    It dissolves extremely well in water and doesn't separate out in layers, because it has an -OH group that can form hydrogen bonds with the adjacent water molecules. If you have an impure sample, it won't separate out into a layer of clean sample with gunk dissolved in water.

    I'm not sure how the mark scheme rubric wants it to be stated, but I'd imagine it's something like

    1. Ethanoic acid dissolves in water (due to h-bonding)
    2. Therefore it will not separate when shaken with water
    3. So impurities cannot be isolated (and removed) using a separating funnel
    Thank you very much for the help and thorough answer, I really appreciate it!
 
 
 
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