General Chemistry 2

Question

When the following equation is balanced properly under basic conditions, what are the coefficients of the species shown?

 Cl^- +  S   ClO^- +  S^2-

Water appears in the balanced equation as a fill in the blank 5 (reactant, product, neither) with a coefficient of . (Enter 0 for neither.)

How many electrons are transferred in this reaction? 

Answer 1

Cl^- + S ==> ClO^- + S^2- unbalanced

We will balance the oxidation and reduction half reactions separately:

Cl^- ===> ClO^- ... unbalanced oxidation half reaction

Cl^- + H₂O ==> ClO^- ... balanced for Cl and O

Cl^- + H₂O + 2OH^- ==> ClO^- + 2H2O ... balanced for Cl, O and H using base (OH-)

Cl^- + H₂O + 2OH^- ==> ClO^- + 2H2O + 2e- ... balanced for Cl, O, H and charge

S ==> S^2- ... unbalanced reduction half reaction

S + 2e- ==> S^2- ... balanced for S and charge

Combine the two half reactions

Cl^- + H₂O + 2OH^- + S + 2e- ==> ClO^- + 2H2O + 2e- + S^2-

Combine and cancel like terms to get the final balanced redox equation

Cl^- + 2OH^- + S ==> ClO^- + H₂O + S^2- ... balanced redox equation

Water appears in the balanced equation as a PRODUCT with a coefficient of ONE

There are 2 electrons transferred in this reaction