Answer. The reactions in which products do not recombine to form reactants again are called irreversible reactions. They are represented by putting a single arrow (—>) between the reactants and products. For examples
a. Formation of water from hydrogen and oxygen gases:
2H2(g) + O2(g) 2H2O(1)
b. Decomposition of calcium carbonate into calcium oxide and carbon dioxide:
CaCO3 CaO + CO2
Characteristics of Irreversible Reactions:
i. In these reactions only reactants react to form products.
ii. Reactants are written on the left side and products on the right side.
iii. Products never react to form the reactants again.
iv. These reactions take place from left to right. Left side has the reactants and right side has the products.
v. They are represented by putting a single arrow. (— >) between the reactants and the products.
v. In the beginning reaction rate is fast but gradually slow down.
vi. They stop on the completion of reaction.