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Topic: Why use sodium metabisulfite in copper(I)chloride preparation?  (Read 6512 times)

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Offline Fmeub

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Hi!

Given the following reaction equations:

Na2S2O5 + H2O -> 2NaHSO3

and

2CuSO4.5H2O + 4NaCl + NaHSO3 + NaOH -> 2CuCl + 3Na2SO4 + 2HCl + 10H2O

In the procedure for an experiment I have to do, it says that I mix Na2S2O5 , NaOH and water, and then add this to a hot mixture of CuSO4.5H2O , NaCl and water.

My question is why use sodium metabisulfite (Na2S2O5 ), and not just sodium bisulfite (NaHSO3) or sodium sulfite (Na2SO4) to start with?

Later the CuCl is used in the synthesis of o-chlorobenzoic acid.

Offline AWK

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Re: Why use sodium metabisulfite in copper(I)chloride preparation?
« Reply #1 on: August 04, 2008, 05:13:51 AM »
You should rerduce Cu(II) to Cu(I)
AWK

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