Explanation:
A displacement reaction is the one wherein the atom or a set of atoms is displaced by another atom in a molecule. For instance, when iron is added to a copper sulphate solution, it displaces the copper metal. A + B-C → A-C + B.
D. 18 x 10^23 is the total number of atoms in 1.0 mole of CO2
Helium was discovered in 1868.
