Question

How is chlorine prepared using $KMn{O_4}$?

Answer 1

Hint: $KMn{O_4}$ is a powerful oxidizing agent in neutral, alkaline and acidic medium. So, in an acidic solution, potassium permanganate can oxidize chloride ions to chlorine gas.

Complete step by step answer:
Chlorine gas can be prepared by the action of concentrated $HCl$ and $KMn{O_4}$ in cold.
\[
  2KMn{O_4} + 6HCl \to 2KCl + 2MnC{l_2} + 3{H_2}O + 5[O] \\
  \underline {\,\,\,\,\,\,\,\,\,\,\,\,[2HCl + [O] \to {H_2}O + C{l_2}] \times 5\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,} \\
  2KMn{O_4} + 16HCl \to 2KCl + 2MnC{l_2} + 5C{l_2} + 8{H_2}O\,\,\,\,\, \\
    \\
  \]
Chlorine gas evolved by this process contains impurities of $HCl$ and water vapor. It can be purified by bubbling through water and concentrated${H_2}S{O_4}$. Water absorbs the traces of $HCl$ and concentrated ${H_2}S{O_4}$ absorbs moisture. The $C{l_2}$ thus obtained is collected by the upward displacement of air. This method is generally used in the laboratory to prepare $C{l_2}$.

Note:
Chlorine is the most abundant element in the halogen family. It was discovered by Scheele in 1774. He prepared it by heating $HCl$ and $Mn{O_2}$ then gave the name oxymuriatic acid. Later Davy in 1810 identified it as a new element and gave the name chlorine because of its greenish yellow color. The name ‘Chlorine’ is derived from the Greek word chloros, which means greenish yellow.
Due to its high reactivity nature $C{l_2}$ does not occur in free state in nature.