No chemical reaction takes place when granules of a rusty brown solid `A` are mixed with the powder of another solid `B`. However, when the mixture is heated, a reaction takes place between its components. One of the products `C` is a metal and settles down in the molten state while the other product `D` floats over it. It was observed that the reaction is highly exothermic.
(a) What could the solids `A` and `B` be ?
(b) What are the products `C` and `D` most likely to be ?
(c) Write the chemical equation for the reaction between `A` and `B` leading to the formation of `C` and `D`.
Mention the physical states of all the reactants and products in this equation and indicate the heat change which takes place.
(d) What is the special name of such a reaction ? State one use of such a reaction.
(e) Name any two types of chemical reaction under which the above reaction can be classified.

Explanation

(a) A is iron (III) oxide and B is aluminium (b) C is molten iron metal and D is aluminium oxide (c) , (d) Thermite reaction, welding of broken pieces of heavy iron objects like railway tracks, etc. (e) displacement reaction and oxidation-reduction reaction