Question

Write the balanced chemical equation for the following reaction and identify the type of reaction:
Hydrogen(g) + Chlorine(g) → Hydrogen chloride(g)

Answer 1

Hydrogen(g) + Chlorine(g) → Hydrogen chloride(g)

1. Balancing steps:
Step 1: Write unbalanced equation.
$\mathrm{H}{}_2+\mathrm{Cl}{}_2\to \mathrm{HCl}$

Step 2: Write down the number of atoms of each elements present on both reactant as well as product side.

Element Reactant side Product side
$\mathrm{H}$ $2$ $1$
$\mathrm{Cl}$ $2$ $1$
Step 3: Add coefficients to balance the number of atoms at both the sides
Balance $\mathrm{H}$ and $\mathrm{Cl}$ at product side by adding $2$ before $\mathrm{HCl}$.

$\mathrm{H}{}_2+\mathrm{Cl}{}_2\to 2\mathrm{HCl}$

Balanced equation is:
$\mathrm{H}{}_2(\mathrm{g})+\mathrm{Cl}{}_2(\mathrm{g})\to 2\mathrm{HCl}\left(\mathrm{g}\right)$
(Hydrogen) (Chlorine) (Hydrogen chloride)

2. 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 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. $\mathrm{AB}+\mathrm{CD}\to \mathrm{AD}+\mathrm{CB}$

$\mathrm{H}{}_2(\mathrm{g})+\mathrm{Cl}{}_2(\mathrm{g})\to 2\mathrm{HCl}\left(\mathrm{g}\right)$

Here $\mathrm{H}{}_2$ and $\mathrm{Cl}{}_2$ are combining to form $\mathrm{HCl}$
This is a combination reaction .