Final answer:
The true statement is that reduction reactions occur at the cathode. This is part of electrochemical cell operations where the anode is the site of oxidation, and the cathode is the site of reduction.
Step-by-step explanation:
The accurate statement regarding an electrochemical cell is that reduction reactions occur at the cathode. During electrochemical processes such as those occurring in batteries or electrolysis, two types of electrodes are involved: anode and cathode. At the anode, oxidation takes place which is a process where electrons are lost. Conversely, reduction takes place at the cathode, where electrons are gained. This electrochemical behavior is encapsulated by the cell notation which starts with the reaction at the anode, followed by the reaction at the cathode, such as in the cell notation Cr(s) | Cr³+ (aq)||Cu²+ (aq)| Cu(s).
A redox reaction, or oxidation-reduction reaction, necessarily involves the transfer of electrons between substances. The substance losing electrons is undergoing oxidation, while the one gaining electrons is undergoing reduction. Therefore, statement 4) Reduction reactions occur at the cathode is true.