text: Despite being generally inert, carbon tetrachloride can undergo various reactions. Hydrogen or an acid in the presence of an iron catalyst can reduce carbon tetrachloride to chloroform, dichloromethane, chloromethane and even methane. When its vapours are passed through a red-hot tube, carbon tetrachloride dechlorinates to tetrachloroethylene and hexachloroethane.
  Carbon tetrachloride, when treated with HF, gives various compounds such as trichlorofluoromethane (R-11), dichlorodifluoromethane (R-12), chlorotrifluoromethane (R-13) and carbon tetrafluoride with HCl as the by-product:
  This was once one of the main uses of carbon tetrachloride, as R-11 and R-12 were widely used as refrigerants.
  An alcohol solution of potassium hydroxide decomposes it to potassium chloride and potassium carbonate in water:
  When a mixture of carbon tetrachloride and carbon dioxide is heated to 350 degrees C, it gives phosgene:  A similar reaction with carbon monoxide instead gives phosgene and tetrachloroethylene:
  Reaction with hydrogen sulfide gives thiophosgene:
  Reaction with sulfur trioxide gives phosgene and pyrosulfuryl chloride:
  Reaction with phosphoric anhydride gives phosgene and phosphoryl chloride:
  Carbon tetrachloride reacts with dry zinc oxide at 200 degrees Celsius to yield zinc chloride, phosgene and carbon dioxide: