Description of experiment
Below follows a plain text transcript of the selected experiment.
Needed compounds:
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oxone : K2SO4.KHSO4.2KHSO5
potassium bromide : KBr
propionic acid : CH3CH2COOH
acrylic acid : CH2CHCOOH
Class:
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elem=C,Br
organic
Summary:
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Bromine quickly adds to acrylic acid (which has a double bond, in the molecule H2C=CH-C(O)OH)).
Bromine does not react quickly with propanoic acid.
Description:
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Dissolve some potassium bromide in water. In a separate test tube dissolve some oxone and add this
to the solution of potassium bromide: The liquid becomes deep orange. Also quite some vapor of
bromine is formed above the liquid.
Divide the orange liquid in two equal parts, call these part A and part B.
To part A, add a few big drops of acrylic acid and swirl: Quickly the color of the bromine fades
and the vapor of the bromine also quickly fades.
To part B, add a few big drops of propanoic acid and swirl: The color of bromine persists, the
vapor also remains present.
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This experiment nicely demonstrates that a double bond (-C=C-) easily adds bromine, even when
present in a compound with another functional group and when diluted in a lot of water.