Chapter 15, Problem 77CP

Interpretation Introduction

Interpretation: Use half equations to balance the following equations in acidic solutions:

  ${\text{Cr}}_{\text{2}}{\text{O}}_{\text{7}}{}^{\text{2-}}\left(\text{aq}\right){\text{ + NO}}_{\text{2}}{}^{\text{-}}\left(\text{aq}\right)\to {\text{Cr}}^{\text{3+}}\left(\text{aq}\right){\text{ + NO}}_{\text{3}}{}^{\text{-}}\left(\text{aq}\right)$

Concept introduction:Here are the steps to balance redox reaction sin an acidic medium:

1. Determine the oxidation numbers of the elements to figure out the oxidation and reduction half of the equation.
2. To balance every half reaction in acidic medium, use H₂O to balance O, use H+ to balance H, and finally use electrons to balance the net charge.