Final answer:
The products of the electrolysis of KI and NaCl are potassium (K) and iodine (I2) for KI, and sodium (Na) and chlorine gas (Cl2) for NaCl.
Step-by-step explanation:
The substances produced during the electrolysis of KI (potassium iodide) and NaCl (sodium chloride) can be determined by considering the reactions at the electrodes. For the electrolysis of molten NaCl, the products at the electrodes are sodium (Na) at the cathode and chlorine gas (Cl2) at the anode, as described in the Downs process. However, when KI is electrolyzed, potassium (K) would be produced at the cathode and iodine (I2) at the anode. Thus, the correct answer to the student's question is a) K and I2; Na and Cl2.