(a) What is compound A?
(b) What is compound B?
(c) What is gas C?
(d) What do you think is the black substance X? What is its function?
(e) What is the general name of substances like X?
(b) The compound B is Potassium chloride, KCl.
(c) Gas C is Oxygen, O2.
(d) The black substance is Manganese dioxide, MnO2. It is a catalyst Used in decomposition of potassium Chlorate to form Oxygen gas.
(e) General name for substances like X is catalysts.