\textbf{235 -- Which statement is correct?}
\begin{enumerate}
\item In electroplating, the object to be plated must be placed at the anode.
\item In the electrochemical refining of copper, sulfuric acid plays the role of oxidizing agent.
\item Aluminum is the most abundant metal and the third most abundant element in the Earth's crust.
\item A Down cell is used to prepare sodium from molten sodium chloride.
\end{enumerate}