Chapter 17

Why does a sacrificial anode provide cathodic protection?

What is electroplating?

Assign oxidation numbers to the atoms in the ionic compound MgBr \(_{2}(s) .\)

Assign oxidation numbers to the atoms in the ionic compound \(\mathrm{NH}_{4} \mathrm{NO}_{3}(s) .\)

Assign oxidation numbers to the atoms in the ion \(\mathrm{PF}_{6}^{-}(a q) .\)

Identify each of the following half-reactions as oxidation or reduction reactions. \begin{equation} \begin{array}{l}{\text { a. } \mathrm{K}(s) \rightarrow e^{-}+\mathrm{K}^{+}(a q)} \\ {\text { b. } \mathrm{Cu}^{2+}(a q)+e^{-} \longrightarrow \mathrm{Cu}^{+}(a q)} \\ {\text { c. } \mathrm{Br}_{2}(l)+2 e^{-} \rightarrow 2 \mathrm{Br}^{-}(a q)}\end{array} \end{equation}

Is the reaction below a redox reaction? Explain your answer. $$\mathrm{Ca}(s)+\mathrm{Cl}_{2}(g) \rightarrow \mathrm{CaCl}_{2}(s)$$

Describe how to identify the oxidizing agent and the reducing agent in a reaction.

Nitrogen monoxide, \(\mathrm{NO}(g),\) reacts with phosphorus, \(\mathrm{P}_{4}(s)\) , to produce nitrogen, \(\mathrm{N}_{2}(g),\) and diphosphorus pentoxide, \(\mathrm{P}_{2} \mathrm{O}_{5}\) Write the balanced equation for this reaction. Identify the atoms that have been oxidized and reduced, and identify the oxidizing and reducing agents.

What is the distinction between a half- reaction and an electrode reaction?