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Homework Help: Identifying unknown organic compounds

  1. Sep 15, 2009 #1
    1. The problem statement, all variables and given/known data

    A chemist has three liquids (Ethanol, butanoic acid and 3-heptyne) labelled P,Q,R (in no specific order). When drops of bromine solution were added to samples of each liquid, P and Q decolorised the bromine, but R did not. When drops of sodium carbonate solution were added to fresh samples, R produced bubbles of colourless gas, but P and Q did not. When ap iece of sodium metal was added to fresh samples of the three liquids, P and R produced bubbles of gas, but Q did not.

    Find P, Q, R and give equations for each of the reactions that occurred.

    3. The attempt at a solution

    P - Reacted with Bromine, Reacted with sodium to give gas
    Q - Reacted with Bromine
    R - Gave off bubbles with Na2CO3, Reacted with sodium to give gas

    I'm not sure of the reaction with metallic sodium. What gas is given off when it is added to organic compounds? Also does bromine only react with the butanoic acid and heptyne because they have double/triple bonds??
  2. jcsd
  3. Sep 15, 2009 #2


    User Avatar

    Staff: Mentor

    It can react with slighly acidic protons - similarly to the reaction with water.

    Yes for heptyne, no for butyric acid.


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