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Bromine Properties

Bromine

source : slide player.com

Physical properties of Bromine :

  • It is deep red colored, volatile  liquid.
  • Bromine is poisonous and produces blisters on skin.
  • It has pungent odour.
  • It is soluble in water. Its aqueous solution is called bromine water.

Chemical properties :

1)  Reaction with NH3 : Ammonium bromide & nitrogen is formed.

2NH3 + 3Br2 ——–> N2 + 6HBr

6 HBr + 6NH3   ———–> 6NH4Br

Equation as a whole-

8NH3 +3 Br2 ——-> 6NH4Br +N2

2) Reaction with NaOH :

a)With  Cold and dilute NaOH : Sodium bromide & sodium hypo bromite is formed.

2NaOH +Br2 ——-> NaBr +NaBrO (sodium hypo bromite) + H2O.

b) With hot and concentrated NaOH : Sodium bromide & sodium  bromate is formed.

6NaOH + Br2 —–>5 NaBr +NaBrO3(sodium  bromate) +3 H2O.

3) Reaction with Ba(OH)2 solution (baryta water):

6Ba(OH)2 + 6Br2 —–>5 BaBr2 (barium bromide) +Ba(BrO3)2 (barium    bromate)+ 6H2O.

4) Reaction with hot and concentrated Na2CO3 solution : Sodium bromide & sodium  bromate is formed.

3Na2CO3+ 3Br2 ——-> 5NaBr + NaBrO3 + 3CO2

5) Reaction with Ca(OH)2 :  calcium bromo hypo bromite is formed.

Ca(OH)2 +Br2 ——–> CaOBr2 (calcium bromo hypo bromite) + H2O

6) Oxidizing properties :

In presence of moisture bromine acts as strong oxidizing agent.

a) It oxidizes SO2 into H2SO4:

Br2 +H2O ——->2HBr +O

SO2 + O+ H2O  ——–> H2SO4

Equation as a whole-

Br2 + SO2 +2H2O  —->H2SO4 +2HBr

b) It oxidizes sodium thio sulphate to sodium tetra thionate:

2Na2S2O3(sodium thio sulphate) + Br2  —-> Na2S4O6( sodium tetra thionate) +2NaBr

c) It oxidizes sodium arsenite to sodium arsenate:

Br2 +H2O ——> 2HBr +O

Na3AsO3 +O ——> Na3AsO4

Equation as a whole-

Br2 + H2O + Na3AsO3(sodium arsenite)  ——–> 2HBr +Na3AsO4(sodium arsenate)

d) It displaces I2 from KI:

2KI + Br2 ———>2KBr +I2

Test of bromine:

1)  Bromine is red colored liquid with pungent odour.

2) It turns starch iodide paper blue.

2KI +Br2 ——-> 2KBr + I2

I2 +starch ——> blue color

Uses:

1)  As oxidizing agent.

2) As a germicide.

3) Br2-water is used to test unsaturation in organic compounds.


 

 

 

 

Saroj Bhatia: Dr. Saroj Bhatia is an Ph.D in chemistry who has been teaching chemistry for over a decade. Currently she is a respected principal of a renowned college in her hometown. She took this medium for online users. Her proudest achievement is helping people learn chemistry.
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