[nexisrocks]

I am attempting to balance the preparation of cuprous chloride from CuSO4 by the method of half reactions.  The compound was created by crushing 31g of cupric sulfite pentahydrate and dissolving it in hot water along with 10g of sodium chloride.  Then a sodium bisulfite mixture (7.2g of sodium bisulfate and 4.7g of sodium hydroxide dissolved in water) was slowly added.

I have one half reaction:

Cu²⁺ + e^- --> Cu⁺
SO₄^2- --> HSO₃^- + e^-
Cu²⁺ + SO₄^2- --> Cu⁺ + HSO₃⁺

However, I am unsure as to how to do the rest.  I know my products are HCuCl₂ and H₂SO₄.  The NaCl cannot be a solvent because it is the only compound with Cl; thus it must be the one to contribute the Cl to the final product.  But why do we have sodium bisulfite and sodium hydroxide?  Why do we heat the cupric sulfate solution?

I had originally thought that water was just a solvent, but now I am unsure; where else would the hydrogens come from in the products?  Heat could suggest that hydrogen atoms are grabbed.  However, could it be the hydrogen from sodium bisulfite instead?

I am unsure how this reaction occurs (ie what steps occur) and because of this I cannot complete the half-reaction method.

Can anyone help me figure out the rest of the half-reactions?

Thanks!

[UnintentionalChaos]

Are you sure it wasn't bisulfite? Sulfite is a good reducing agent and would make sense. The sodium hydroxide seems largely irrelevant unless I am overlooking something.

[nexisrocks]

Oops!  I'm sorry!

You're right, it is sodium bisulfite.  I've changed it in the original post - thanks for pointing that out!

Because sodium bisulfite is a good reducing agent, it would reduce the copper from Cu(II) to Cu(I), correct?  And that would be the half reaction I already have?

But if it is the half reaction I already have, how did I start with SO_42- instead of HSO₃^- (which is the dissociated form of sodium bisulfate)?

[Borek]

Oxidation half reaction must be built around sulfite oxidation: SO₃^2- -> SO₄^2-