Prepare a pure sample of Iodoform (CHI3) from ethyl alcohol or acetone.

 Prepare a pure sample of Iodoform (CHI3) from ethyl alcohol or acetone.

Iodoform can be prepared by heating ethyl alcohol or acetone with iodine in the presence of sodium hydroxide or sodium carbonate solution. The iodoform yellow precipitate separated after being heated for 15 minutes. It is separated by filtration on a Buchner funnel with the help of a suction pump.

Chemical equations :

CH₃COCH₃ + 4I₂ + 4NaOH → CHI₃  + CH₃COONa + 3NaI  + 2H₂O

 Requirement:

Apparatus: 250 ml round-bottomed flask. 250 ml beaker, filtration flask, water bath. tripod stand, Buchner funnel, water pump 

 

Chemicals:

      Acetone = 5.0 ml, Iodine (powder) , Sodium hydroxide= 10% , Rectified spirit

Procedure:

• Take 2 mL acetone and 30 mL of 10% NaOH in a 250 mL conical flask. 
• Add 5 % sodium hydroxide solution slowly with shaking until the colour of iodine is discharged. 
• Allow it to stand at room temperature for 2-3 minutes. 
• Filter the yellow precipitate of iodoform using funnel. 
• Wash it with water twice and crude iodoform is obtained. 

Result:

• Yield of crystals – 5 g 
•  Melting point – 119 ◦C.

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