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Chlorine Property : Physical and Chemical Properties | Uses

Chlorine Property : Physical

It is a greenish-yellow color with a pungent odor and a poisonous gas.

It is soluble in water. Its aqueous solution is called chlorine water.

It is heavier than air and oxygen.

It changes into liquid state at -34.5°C and into solid state at –101.5°C.


Chlorine Property : Chemical


Chlorine gas does not burn on its own but helps in burning some substances.

Example: Putting a piece of burning sulfur in a jar filled with chlorine gas and closing the jar, it continues to burn.

2S + Cl2 → S2Cl2 (Sulfur Monochloride)

Reaction with non-metals

It reacts with most of the non-metals to form their chlorides.

Example: With sulfur it forms sulfur mono chloride.

2S + Cl2 → S2Cl2 (Sulfur Monochloride)

When white phosphorus is poured into a jar filled with chlorine gas, it rises and chlorides of phosphorus are formed.

2P + 3Cl2 → 2PCl3 (phosphorus tri-chloride)

2P + 5Cl2 → 2PCl5 (phosphorus penta-chloride)

In the presence of sunlight with hydrogen it reacts with great intensity or explosion and forms hydrogen chloride gas.

H2 + Cl2 → 2HCl

Reaction with metals

Almost all metals react with chlorine to form their chloride salts. In these reactions chlorine gas is passed over metals in their hot states.

2Al + 3Cl2 → 2AlCl3

Cu + Cl2 → CuCl2

2Na + Cl2 → 2NaCl

Zn + Cl2 → ZnCl

Mg + Cl2 → MgCl2

Reaction with Water

Chlorine is soluble in water and its aqueous solution is called chlorine water. By keeping chlorine water in strong sunlight or in the presence of catabolists, the action of chlorine and water starts and oxygen gas is obtained.

Cl2 + H2O → HCl + HClO (Hypochlorous Acid)

HClO → HCl + O

O + O → O2

Reaction with sodium hydroxide

When passed in cold and dilute sodium hydroxide solution, it forms sodium hypochlorite(NaOCl).

Cl2 + 2NaOH → NaCl + NaOCl + H2O


On passing through hot and concentrated sodium hydroxide solution, it forms sodium chlorate(NaClO3).

3Cl2 + 6NaOH → NaClO3 + 5NaCl + 3H2O

Reaction with slaked lime

When flown over dry slaked lime, it forms bleaching powder.

Cl2 + Ca(OH)2 → CaOCl2 + H2O

Reaction with ammonia

It reacts with ammonia to form ammonium chloride and nitrogen.

2NH3 + 3Cl2 → N2 + 6HCl

6NH3 + 6HCl → 6NH4Cl

XXX ======= XXX ======== XXX

3Cl2 + 8NH3 → 6NH4Cl + N2

If this excess amount of chlorine is processed with less amount of ammonia, then nitrogen trichloride(NCl3) is formed which is a very explosive substance.

3Cl2 + NH3 → NCl3 + 3HCl

Oxidizing Properties

Chlorine is a strong oxidising agent and it oxidizes various substances.


potessium bromide into bromine

2KBr + Cl2 → 2KCl + Br2

Potassium iodide is converted into iodine

2KI + Cl2 → 2KCl + I2

hydrogen sulfide to sulphur

H2S + Cl2 → 2HCl + S

The sodium sulfite solution is converted into sodium sulfate

Na2SO3 + Cl2 + H2O → Na2SO4 + 2HCl

ferrous sulfate to ferric sulfate

Cl2 + 2FeSO4 + H2SO4 → Fe2(SO4)3 + 2HCl

Aqueous solution of sulfur dioxide to sulfuric acid

SO2 + 2H2O + Cl2 → 2HCl + H2SO4

Chlorine Property : Addition Compounds

It forms addition compounds with carbon monoxide, sulfur dioxide and unsaturated carbolic compounds.

CO + Cl2 → COCl2 (Carbonyl chloride – Phosgene)

SO2 + Cl2 → SO2Cl2 (Sulfuryl Chloride)

C2H4 + Cl2 → C2H4Cl2 (Ethylene Dichloride)

Chlorine Property : Substitution Reactions

The reactions in which one or more hydrogen atoms of a compound are replaced by other atoms or groups are called substitution reactions. Chlorine exhibits substitution reactions with various carbonic compounds.

example :

CH4 + Cl2 → CH3Cl + HCl

Bleaching Properties

Being a strong oxidising agent, it is also a strong bleach. It spoils the color of wet flowers, leaves etc.

In this process, first this moisture reacts with H2O to produce nascent oxygen and then this nascent oxygen reacts with the colored components of flowers, leaves, etc. to oxidize them and make them colourless.

H2O + Cl2 → 2HCl + O

Coloured component + O → Colourless Component

Chlorine Uses

Chlorine gas is used in the manufacture of important compounds like bleaching powder, bromine, chloroform, carbon tetra chloride, phosjine, etc.

It is used for the purification of drinking water as a disinfectant.

Chlorine gas and chlorine water are used as a reagent in the laboratory.

It is also used in metal extraction and refining.

It is also used in making dyes and explosives.

It is used to make phosjin and musterd gas. Both these gases are very toxic. Musturd gas was used in the First World War. The composition formula of musturd gas is as follows –

Chlorine gas is used as a bleach for bleaching paper, clothing, etc.

Sanjay Bhandari

Hello Friends, My name is Sanjay Bhandari. I am a chemistry Teacher.

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