Question

No chemical reaction takes place when granules of a 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.

(i) Based on the given information make an assumption about A and B and write a chemical equation for the chemical reaction indicating the conditions of reaction, physical state of reactants and products and thermal status of reaction.

(ii) Mention any two types of reactions under which above chemical reaction can be classified.

Answer 1

(i) Solid A is assumed to be MnO₂ and solid B to be Aluminium (Al).

When the mixture of MnO₂ and Al is heated, manganese (Mn) is produced in molten state and aluminium oxide (Al₂O₃) floats over it. Mn is produced in the molten state as a lot of heat energy is released in the process.

The chemical equation for the reaction can be written as:

3MnO_2(s) + 4Al_(s) `triangle/`> 3Mn_(f) + 2Al₂O_3(s) + Heat

(ii) The types of reaction under which the above reaction is classified are—

1. Redox reaction

2. Displacement reaction