Chemical Test For Chlorine 2

2) Displacement reactions : Chlorine can displace bromide and iodide ions from  a metal halide compounds.

Chlorine gas is passed through the solution of bromide ions:

Cl₂ (g)  +    2KBr  (aq)  →  2KCl(aq)  +     Br₂ (aq)         

Notes

·         Bromine gas i.e formed here is soluble in water. ·         To Identify the spectator ions,  we need to consider some facts: 1) State Symbols 2) Oxidation no. of components         in   a redox reaction.

 

                                                   

Ionically,

Cl₂ (g) + 2Br^- (aq)      →   2Cl^- (aq) + Br₂ (aq)

At the end of the reaction , if the product mixture is shaken with CCl₄ / Hexane/ Cyclohexane /, Two coloured layers are observed. 

Chlorine gas is passed through the solution of iodide ions:

Cl₂ (g)  +    2KI  (aq)  →  2KCl(aq)  +     I₂ (aq)              

Notes

·         To Identify the spectator ions,  we                  need to consider some facts: 1) State Symbols 2) Oxidation no. of components in  a redox reaction.

Ionically,

Cl₂ (g) + 2I^- (aq)      →   2Cl^- (aq) + I₂ (aq)

*  Iodine i.e formed here is actually soluble in KI Solution but insoluble in water.

I₂ (s)     +     KI (aq)    →  KI₃ (aq)

                                             Potassium triiodide

Ionically,  

I₂ (s)       +       I^- (aq)     →      I₃^- (aq)

                                         Triiodide Ion

At the end of the reaction , if the product mixture is shaken with CCl₄ / Hexane/ Cyclohexane /, Two coloured layers are observed.

    ** It is the  I₃^- (aq) triiodide ion that gives the yellow colour not the iodine itself.