How will you test pure chloroform?

To test the purity of chloroform (CHCl₃), chemists use both physical and chemical methods.

Physical test:

• Boiling point check: Pure chloroform boils at about 61.2°C. A significant deviation suggests the presence of impurities.
• Smell: Pure chloroform has a characteristic sweet smell, but odor alone is not reliable due to the toxic nature of the vapors.

Chemical test:

• Carbylamine reaction (for impurities): Pure chloroform should not give a carbylamine reaction unless mixed with primary amines.
• Silver nitrate test: When boiled with alcoholic KOH and treated with AgNO₃, formation of white precipitate of AgCl indicates the presence of chloroform.

Safety note: Chloroform is toxic and potentially carcinogenic. Testing must be done in a well-ventilated fume hood with proper PPE (gloves, goggles, lab coat). In modern labs, GC (Gas Chromatography) is the preferred method for detecting impurities in chloroform accurately.