For an example of charge balance in my text it says

Question

For an example of charge balance in my text it says

Write a charge balance eqzn for an aqueous sol that contains NaCl,
Ba(ClO₄)₂, & Al₂(SO₄)₃

The answer given is:
[Na+] + [H30+] + 2[Ba+] + 3[Al3+]= [ClO4-] + [NO3-] + 2[SO42-] + [HSO4-] + [OH-]

I know that the rxns are:

NaCl=> Na+ + Cl-

Ba(ClO4)2 => 2Ba²⁺ + 2ClO4-

Al2(SO4)₃ => 2Al3+ + 3SO4^2-
SO4^2- + H2O => H2SO4- + OH-

The thing is I don't know how they get [NO3] from these being combined together
=/
Maybe I forgot an rxn? b/c the rxn's aren't shown, just the answer...

2H2O => H3O+ + OH-

The answer book goofed. NO3^- doesn't belong and Cl^- has been omitted. I suspect the original salt was NaNO3 and not NaCl. I think the answer then would be ok.

Thanks Dr.Bob, I was wondering where they got the NO3 from

Answer 1

You're welcome! It seems like there may have been a mistake in the answer book. The inclusion of NO3^- in the charge balance equation is incorrect. Based on the given reactions, the correct charge balance equation should include Cl^- and not NO3^-.

The corrected charge balance equation would be:

[Na+] + [H3O+] + 2[Ba^2+] + 3[Al^3+] = [Cl^-] + 2[ClO4^-] + 2[SO4^2-] + [HSO4^-] + [OH^-]

The presence of NO3^- is not accounted for in the given reactions, so it should not be included in the charge balance equation.

Answer 2

It seems that there might be an error in the answer provided in the text. Based on the chemical reactions you have provided, there is no source for the nitrate ion (NO3-) in the given mixture of NaCl, Ba(ClO4)2, and Al2(SO4)3. It looks like the original salt might have been NaNO3 instead of NaCl.

If we assume that the initial salt is NaNO3, then the charge balance equation would be:

[Na+] + [H3O+] + 2[Ba2+] + 3[Al3+] = [NO3-] + [Cl-] + 2[ClO4-] + 3[SO42-] + [HSO4-] + [OH-]

This equation takes into account the dissociation reactions of NaNO3, Ba(ClO4)2, and Al2(SO4)3, as well as the autoionization of water to form H3O+ and OH- ions.

Please note that without further clarification or additional reactions, it is difficult to determine the correct charge balance equation. It would be best to consult your teacher or textbook for clarification.