What is the cause of the color change observed when #HCl# is added to the complex ion #[Cu(NH_3)_4]^(2+)#?

1 Answer
Jul 18, 2017

Answer:

I have explained a similar ligand displacement reaction to this in the answer below:

Explanation:

https://socratic.org/questions/hydrochloric-acid-copper-ll#415291

In this case the complex we have is tetraammine copper(II):

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If excess chloride ions are added the ammonia ligands are displaced and the green, tetrachloro copper(II) complex forms:

#sf(color(blue)([Cu(NH_3)_4(H_2O)_2]^(2+))+4Cl^(-)rarrcolor(green)([CuCl_4]^(2-))+4NH_3+2H_2O)#

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The solution looks like this:

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