Description of experiment
Below follows a plain text transcript of the selected experiment.
Needed compounds:
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cupric chloride dihydrate : CuCl2 . 2H2O
acetyl chloride : CH3COCl
copper sulfate penta hydrate : CuSO4 . 5H2O
Class:
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elem=C,S,Cl,Cu
acid/base
coordination
Summary:
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Acetyl chloride is capable of dehydrating copper(II) chloride, and it even is
capable of replacing sulfate ion by chloride, itself being converted to acetyl
sulfate.
Description:
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Put some solid CuCl2.2H2O in a test tube and add some acetyl chloride, just
enough to cover all of the solid material: The solid material turns green and
no further reaction seems to occur.
Carefully heat the test tube: Bubbles of a colorless gas are produced on the
solid and the color of the solid shifts from green to chocolate brown. The
colorless gas is HCl, copious fumes are produced near the open end of the test
tube.
Add a small quantity of water: All of the brown solid fairly quickly dissolves,
the solution becomes green like grass and becomes clear.
Add more water: The solution becomes clear and light blue.
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Put some solid CuSO4.5H2O in a test tube and add some acetyl chloride: The
bright blue solid becomes green like grass and later on the color slowly shifts
to brown. During the reaction bubbles of HCl are produced.
Add a small quantity of water: An extremely violent reaction occurs, with
crackling noise and all of the brown solid dissolves. A clear green solution is
obtained.
Add more water: A light blue solution is obtained.
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Put some solid CuSO4.5H2O in a test tube and fairly strongly heat, until the
solid has become completely off-white. All water is driven off and anhydrous
CuSO4 is obtained.
Take the dry CuSO4 and put this in a perfectly dry hot test tube. Let all of
the material cool down and when it is back to room temperature, add a small
quantity of acetyl chloride: A soft hissing noise is produced and the white
solid becomes chocolate brown at once. No gas is produced.
Add a small quantity of water: An extremely violent reaction occurs, with
crackling noise and all of the brown solid dissolves. A clear green solution is
obtained.
Add more water: A light blue solution is obtained.
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With CuCl2.2H2O, the following reaction occurs:
CuCl2.2H2O + 2CH3COCl --> CuCl2 + 2HCl + 2CH3COOH
With CuSO4 the following reaction occurs:
CuSO4 + 2CH3COCl --> CuCl2 + (CH3CO)2SO4
With hydrated CuSO4.5H2O the same reaction occurs, but the water at the same
time reacts, giving acetic acid and HCl.
Acetyl sulfate causes the extremely violent reaction with water.