When elemental chlorine ( ) gas is bubbled into a hot and concentrated solution of sodium hydroxide, — Redox Reactions and Volumetric Analysis Chemistry Question

💡 Solution & Explanation

In a hot and concentrated alkali medium, chlorine disproportionates into chloride ( $Cl^-$ ) and chlorate ( $ClO_3^-$ ) ions. The fully balanced reaction is $3Cl_2 + 6OH^- \to 5Cl^- + ClO_3^- + 3H_2O$ . The oxidation state of chlorine in $Cl^-$ is $-1$ , and in the highly oxidized oxoanion $ClO_3^-$ it is $+5$ . (Note: A cold and dilute alkali medium would selectively yield hypochlorite, $+1$ ).