Iodination of methane is reversible. Explain why.
Answer : Methane reacts with iodine to give methyl iodide (iodomethane) and hydrogen iodide (HI). Hydrogen iodide being a strong reducing agent converts iodomethane back to methane.
Iodination of methane may, however, be carried out in the presence of an oxidizing agent such as HIO3, HNO3, HgO etc., which oxidizes the HI formed to iodine.