Question

Write the balanced chemical equations for the below reaction and identify the reaction in the case: Chlorine gas is passed in an aqueous Potassium Iodide solution to form Potassium Chloride solution and solid Iodine.

Answer 1

Balanced chemical reaction:

• A balanced chemical equation is an equation where the number of atoms on the reactant and product side should be an equal number.

Chemical reaction:

• When chlorine gas is passed over aqueous potassium iodide gives aqueous potassium chloride and solid iodine.
• The above reaction is a displacement reaction
• It is a displacement reaction because the iodine in the potassium iodide $\mathrm{KI}$ is displaced by chlorine ${\mathrm{Cl}}_2$.
• The more reactive chlorine displaces the iodine in potassium iodide.

$$\begin{gathered} \mathrm{KI}{\left(\mathrm{aq}\right)}_{}+{\mathrm{Cl}}_2\left(\mathrm{g}\right)\to \mathrm{KCl}\left(\mathrm{aq}\right)+{\mathrm{I}}_2\left(\mathrm{s}\right) \\ (\mathrm{Potassium}(\mathrm{Chlorine}(\mathrm{Potassium}(\mathrm{Iodine}\left) \\ \mathrm{iodide}\right)\mathrm{gas})\mathrm{chloride}) \end{gathered}$$

• Check the number of atoms in the reactant and the product side

The chemical element	L.H.S.	R.H.S
$\mathrm{K}$	$1$	$1$
$\mathrm{Cl}$	$2$	$1$
$\mathrm{I}$	$1$	$2$

• The potassium in the reactant and the product side is not balanced
• By balancing the potassium, we get a balanced equation

$2\mathrm{KI}\left(\mathrm{aq}\right)+{\mathrm{Cl}}_2\left(\mathrm{g}\right)\to 2\mathrm{KCl}\left(\mathrm{aq}\right)+{\mathrm{I}}_2\left(\mathrm{s}\right)$

The chemical element	L.H.S.	R.H.S
$\mathrm{K}$	$2$	$2$
$\mathrm{Cl}$	$2$	$2$
$\mathrm{I}$	$2$	$2$

• Hence the balanced chemical equation is:

$2\mathrm{KI}\left(\mathrm{aq}\right)+{\mathrm{Cl}}_2\left(\mathrm{g}\right)\to 2\mathrm{KCl}\left(\mathrm{aq}\right)+{\mathrm{I}}_2\left(\mathrm{s}\right)$