Question

What is the oxidation number of chlorine? Explain with examples.

Answer 1

Oxidation number:

• It represents the number of electrons lost or gained by the atoms of an element in a compound.
• It is usually written with the sign $(+)$ and $(-)$ first and then the magnitude.

Chlorine:

• It is an element that belongs to the p-block and non-metal.
• It shows a variable oxidation state.
• The oxidation number of chlorine can be $-1,0,+1,+3,+4,+5,\mathrm{or}+7$ which depends on the substance containing the chlorine.

Examples:

• The common oxidation state of chlorine are $-1$ (in the case of $\mathrm{HCl}$ and $\mathrm{NaCl}$) and $0$ (in the case of ${\mathrm{Cl}}_2$).
• The examples of other oxidation states of chlorine are shown below:

$$\begin{gathered} +1\mathrm{in}\mathrm{case}\mathrm{of}{\mathrm{Cl}}_2\mathrm{O} \\ +3\mathrm{in}\mathrm{case}\mathrm{of}{\mathrm{NaClO}}_2 \\ +4\mathrm{in}\mathrm{case}\mathrm{of}{\mathrm{ClO}}_2 \\ +5\mathrm{in}\mathrm{case}\mathrm{of}{\mathrm{NaClO}}_3 \\ +7\mathrm{in}\mathrm{case}\mathrm{of}{\mathrm{Cl}}_2{\mathrm{O}}_7 \end{gathered}$$