Question

Why is chloroform stored in brown bottles?

Answer 1

1. Light Sensitivity: Chloroform (CHCl₃) decomposes when exposed to light, especially UV light.
2. Formation of Toxic Products: Chloroform is stored in brown bottles because it undergoes photochemical oxidation in the presence of sunlight (or UV light) to produce phosgene gas (COCl₂), which is highly toxic.
3. Protective Role of Brown Bottles: Brown (amber) bottles absorb and block UV and visible light, minimizing chloroform’s photodecomposition.
4. Chemical Stability: Using dark-colored bottles preserves the purity, stability, and safety of chloroform during storage.
5. Decomposition reaction:
   \[2 \mathrm{CHCl}_3 + \mathrm{O}_2 \xrightarrow{\text{light}} 2 \mathrm{COCl}_2 + 2 \mathrm{HCl}\]
   So, the brown bottle acts as a protective barrier against light, maintaining the stability and safety of chloroform