One electrode in an alkaline battery is zinc, and the other is manganese dioxide. Fill in the blank for the chemical reaction \((a)\) at the zinc electrode: \(\mathrm{Zn}+2 \mathrm{OH}^{-} \rightarrow\) \(\mathrm{ZnO}+\ldots+2 \mathrm{e}^{-}\)and \((b)\) at the manganese electrode: \(2 \mathrm{MnO}_{2}+\mathrm{H}_{2} \mathrm{O}+\longrightarrow \rightarrow \mathrm{Mn}_{2} \mathrm{O}_{3}+2 \mathrm{OH}^{-}\). (c) Which electrode is positive and which is negative?