Prepare Iodoform.

 

Abstract:

This experiment aims to prepare iodoform from acetone using iodine and sodium hydroxide solution.

Introduction:

Iodoform, also known as triiodomethane, is a yellow solid with a characteristic odor. It is commonly used as an antiseptic. The preparation of iodoform involves the reaction of acetone with iodine and a base such as sodium hydroxide. This reaction proceeds through a series of steps, ultimately resulting in the formation of iodoform.

Experimental Details:

Procedure:

1. Preparation of Reagents:
• Prepare a solution of sodium hydroxide (NaOH) by dissolving a calculated amount of NaOH pellets in distilled water. Ensure the solution is cold.
• Prepare a solution of iodine (I₂) by dissolving iodine crystals in a mixture of acetone and water. The acetone serves as a solvent.
2. Reaction:
• In a clean conical flask, add a measured volume of acetone (CH₃COCH₃).
• Slowly add the iodine solution dropwise while continuously swirling the flask. The solution should turn yellow-brown as iodine is added.
• After adding iodine, add the sodium hydroxide solution dropwise while continuing to swirl the flask. A yellow precipitate of iodoform should form.
3. Isolation of Iodoform:
• Filter the yellow precipitate of iodoform using a Buchner funnel and wash it with cold water to remove impurities.
• Dry the iodoform crystals by pressing between filter papers and then air-drying.

Observations and Calculations:

• Observations: Formation of yellow precipitate (iodoform) during the reaction.
• Calculations: The yield of iodoform can be calculated by determining the mass of the isolated iodoform crystals.

Conclusion:

The experiment successfully demonstrated the preparation of iodoform from acetone using iodine and sodium hydroxide solution. The yellow precipitate obtained was confirmed to be iodoform.

Precautions:

• Handle iodine with care as it is toxic and can stain skin and clothing.
• Avoid inhalation of iodine vapor.
• Perform the reaction in a well-ventilated area to disperse any iodine vapor.
• Use cold solutions of sodium hydroxide and acetone to prevent excessive heating.

Short Questions:

1. What is the chemical name of iodoform?
   Answer: Triiodomethane
2. What are the reagents required for the preparation of iodoform?
   Answer: Acetone, iodine, sodium hydroxide
3. What is the color of the precipitate formed during the preparation of iodoform?
   Answer: Yellow
4. Why is acetone used as a solvent in the preparation of iodoform?
   Answer: To dissolve iodine
5. What is the role of sodium hydroxide in the preparation of iodoform?
   Answer: To provide alkaline conditions for the reaction
6. How is iodoform isolated from the reaction mixture?
   Answer: By filtration and washing with cold water
7. What precaution should be taken while handling iodine?
   Answer: Handle with care as it is toxic and can stain skin and clothing
8. What is the characteristic odor of iodoform?
   Answer: Pungent
9. What type of reaction is involved in the preparation of iodoform?
   Answer: Halogenation
10. What is the color of the solution when iodine is added during the reaction?
    Answer: Yellow-brown
11. How can the yield of iodoform be calculated?
    Answer: By determining the mass of the isolated iodoform crystals
12. Why is the reaction mixture kept cold during the experiment?
    Answer: To prevent excessive heating and ensure controlled reaction conditions
13. What is the appearance of iodoform crystals?
    Answer: Yellow solid
14. What is the chemical formula of acetone?
    Answer: CH₃COCH₃
15. What is the purpose of air-drying the iodoform crystals?
    Answer: To remove residual moisture
16. What type of compound is iodoform?
    Answer: Haloform
17. What is the pH of the reaction mixture during the formation of iodoform?
    Answer: Alkaline
18. What is the chemical name of sodium hydroxide?
    Answer: Caustic soda
19. What is the odor of iodoform?
    Answer: Pungent, characteristic
20. What is the appearance of the reaction mixture during the addition of sodium hydroxide?
    Answer: Formation of yellow precipitate

Multiple Choice Questions (MCQs):

1. Which solvent is commonly used to dissolve iodine for the preparation of iodoform?
   a) Water
   b) Ethanol
   c) Acetone
   d) Hexane
   Answer: c) Acetone
2. What is the color of the precipitate formed during the preparation of iodoform?
   a) White
   b) Yellow
   c) Brown
   d) Green
   Answer: b) Yellow
3. What is the role of sodium hydroxide in the preparation of iodoform?
   a) Acidify the reaction mixture
   b) Act as a reducing agent
   c) Provide alkaline conditions
   d) Precipitate the iodoform
   Answer: c) Provide alkaline conditions
4. What is the chemical name of acetone?
   a) Ethanol
   b) Methanol
   c) Propanone
   d) Butanone
   Answer: c) Propanone
5. What is the appearance of iodoform crystals?
   a) White solid
   b) Yellow solid
   c) Green solid
   d) Red solid
   Answer: b) Yellow solid