Answer
a) N in NH$_{4}$$^{+}$ is the reducing agent. N in NO$_{2}$$^{-}$ is the oxidizing agent.
b) Pb is the oxidizing agent. I$^{-}$ is the reducing agent.
Work Step by Step
a) N in NH$_{4}$$^{+}$ is the reducing agent. N in NO$_{2}$$^{-}$ is the oxidizing agent.
b) Pb is the oxidizing agent. I$^{-}$ is the reducing agent.
