Balance the following redox equation, identifying the element oxidized and the element reduced. Show all of the work used to solve the problem. Ag + CN - + O2 yields Ag (CN) 2 - + H2O

Ag+C N - + O2 ⟹Ag (CN) - 2 + H2 O

On the left side, Ag has an oxidation number of 0 because it is in it's elemental form. Now we check on the right side for the oxidation number of Ag. The Ag (CN) 2 ion has an oxidation number of - 1. CN has an oxidation number of - 1. There are 2x CN so that makes 2-. The overall charge on the ion is - 1 so therefore, Ag has to be + 1 (becaues 1-2 = - 1). Now we know that Ag goes from 0 to + 1 The increase of oxidation number is called oxidation (electrons are lost because they're negatively charged) Now CN stay's the same so it's called a spectator ion. The only one left is oxygen. We see it's in it's elemental state before the arrow so it has an oxidation number of 0. After the arrow it's combined with hydrogen. In a molecule, hydrogen always has oxidation number + 1 and oxygen always has - 2. There are 2 hydrogen atoms so that makes 1+1-2=0. So oxygen goes from 0 to - 2 The oxidation number is decreased, this means electrons are gained and thus oxygen is reduced.