Question

What is the final, balanced equation that is formed by combining these two half reactions?

2 equations: first: upper C u right arrow upper C u superscript 2 plus, plus 2 e superscript minus. Second: upper N upper O subscript 3 superscript minus, plus 2 e superscript minus, plus 2 upper H superscript plus right arrow upper n upper O subscript 2 superscript minus plus upper H subscript 2 upper O.
Upper C u superscript 2 plus, plus upper N upper O subscript 3 superscript minus, plus 4 e superscript minus, plus 2 upper H superscript plus right arrow upper C u plus upper N upper O subscript 2 superscript minus, plus upper H subscript 2 upper O.
Upper C u plus upper N upper O subscript 3 superscript minus, plus 2 upper H superscript plus right arrow upper C u superscript 2 plus, plus upper N upper O subscript 2 superscript minus, plus upper H subscript 2 upper O.
2 upper C u plus upper N upper O subscript 3 superscript minus plus 2 upper H superscript plus right arrow 2 upper C u superscript 2 plus, plus upper N upper O subscript 2 superscript minus, plus upper H subscript 2 upper O.
Upper C u plus upper N upper O subscript 3 superscript minus, plus 2 upper H superscript plus right arrow upper C u superscript 2 plus, plus upper N upper O subscript 2 superscript minus, plus 2 upper H subscript 2 upper O.

Answer 1

Cu + NO3^- + 2 H+ → Cu^{2+} + NO2^- + H2O

Reason: add the half-reactions Cu → Cu^{2+} + 2 e^- and NO3^- + 2 e^- + 2 H+ → NO2^- + H2O; the 2 e^- cancel. Atoms and charge are balanced (total charge = +1 on both sides).