Chlorine : Properties

Chlorine

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Chemical Properties of Chlorine :

1) Reaction with dry SO₂ : sulphuryl chloride is formed.

SO₂ +Cl₂ ——–> SO₂Cl₂ (sulphuryl chloride)

2) Reaction with carbon monoxide:

CO +Cl₂ ———> COCl₂ (carbonyl chloride)

3) Reaction with dry slaked lime Ca(OH)₂ :  We get bleaching powder

Ca(OH)₂ +Cl₂ ——>CaOCl₂ (bleaching powder)  +H₂O

4) Reaction with lime water : 

a) with cold lime water : calcium chloride  & Calcium hypo chlorite is formed.

2Ca(OH)₂  +2Cl₂  ——–> CaCl₂ (calcium chloride) +Ca(OCl₂)₂ (Calcium hypo chlorite) +2H₂O

b) with hot lime water : calcium chloride  & Calcium  chlorate is formed.

6Ca(OH)₂ +6Cl₂ ——–>  5CaCl₂  +Ca(ClO₃)₂ ( calcium chlorate)+6H₂O

5) Reaction with NaOH :

a) With cold and dilute NaOH :  Sodium  chloride  & sodium hypo chlorite is formed.

2NaOH +Cl₂  ——–> NaCl  +NaClO (sodium hypo chlorite)+H₂O

b) With hot and concentrated NaOH :   Sodium  chloride  & sodium  chlorate is formed.

NaOH +Cl₂   ————> NaCl + NaClO₃ (sodium chlorate) +H₂O

6) Reaction with Ammonia :

a) With excess of NH3 : Nitrogen & ammonium chloride is formed .

2NH₃ + 3Cl₂  ——>N₂  +6HCl

6HCl +6NH₃ ——–> 6NH₄Cl

Equation as a whole-

8NH₃ + 3Cl₂ ——-> N₂ +6NH₄Cl

b) With excess of Cl_{2 :  nitrogen tri-chloride is formed which is used as explosive.}

NH₃ + 3Cl₂ ——–> NCl₃ (nitrogen tri-chloride )(explosive) +3HCl

Oxidizing Properties:

It is presence of moisture chlorine acts as strong oxidizing agent.

a) It oxidizes H₂S into S :

Cl₂ +H₂O ——–> 2HCl +O

H₂S +O ——> H₂O +S

Equation as a whole –

Cl₂ + H₂S    ——>2HCl + S

b) It oxidizes ferrous chloride into ferric chloride :

2FeCl₂ +Cl₂ ——-> 2FeCl₃

c) It oxidizes acidic ferrous sulphate to ferric sulphate :

Cl₂ +H₂O ——->2HCl+ O

2FeSO₄ + H₂SO₄ +O  —-> Fe₂(SO₄)₃ + H₂O

Equation as a whole –

2FeSO₄ +H₂SO₄ +Cl₂  —-> Fe₂(SO₄)₃ +2HCl

d) It oxidizes  sodium  sulphite  to sodium sulphate :

Na₂SO₃ +Cl₂ +H₂O  ——>Na₂SO₄ +HCl

e) It oxidizes KBr into Br₂ and KI into I_{2 :}

2KBr +Cl₂   ——> 2KCl +Br₂

2KI + Cl₂ ——> 2KCl +I₂

Bleaching Properties:

In presence of moisture Cl₂ acts as bleaching agent. Its bleaching action is due to its oxidizing properties. It bleaches colored flowers , leaves , wood pulp etc.

Cl₂+ H₂O ——–>2HCl + O (Nascent oxygen)

colored substance + O  ——-> colorless substance

Test of chlorine:

1. It bleaches colored flowers, leaves, wood pulp etc.

2. It turns starch iodide paper blue or violet. Starch- iodide paper contains  starch &  KI solution.

2KI +Cl₂    ——–> 2KCl + I₂.

I₂ +starch ——-> blue color.

3. Aqueous solution of chlorine turns blue litmus red.

Uses :

• It is used as oxidizing agent.
• Chlorine acts as disinfectant and germicide.
• As Bleaching agent.