Question

Identify the type of chemical reaction taking place in each of the following:

Quicklime reacts vigorously with water releasing a large amount of heat.

Answer 1

1. Type of reaction

Combination reaction: Reaction in which two or more reactants combine to form a single product. $\mathrm{A}+\mathrm{B}\to \mathrm{C}$

Decomposition reaction: Reaction in which reactant is broken down into two or more products in the presence of heat, light or electricity. $\mathrm{A}\to \mathrm{B}+\mathrm{C}$

Displacement reaction: Reaction in which one of the higher reactive element displaces a less reactive element from its solution. $\mathrm{A}+\mathrm{BC}\to \mathrm{AC}+\mathrm{B}$ ( Here A is more reactive than B)

Double displacement reaction: Reaction in which ions of both the reactants interchange their place and form new compounds. $\mathrm{AB}+\mathrm{CD}\to \mathrm{AD}+\mathrm{CB}$

2. Reaction

$\mathrm{CaO}\left(\mathrm{s}\right)+\mathrm{H}{}_2\mathrm{O}\left(\mathrm{l}\right)\to \mathrm{Ca}\left(\mathrm{OH}\right){}_2(\mathrm{aq})+\mathrm{Heat}$
Calcium oxide Water Calcium hydroxide
(Quick lime) (Slaked lime)

3. It is a combination reaction (two reactants combining to form a new product) i.e. calcium oxide combining with water and forming calcium hydroxide and it is a highly exothermic reaction (reaction in which heat energy is released along with the formation of product).