Solution
Related Formula
% of Halogen (I) = Atomic weight of IMolecular weight of AgI × Mass of AgIMass of organic compound × 100Core Logic
- Identify the halogen: The violet color in the chloroform layer upon addition of chlorine water is the classic test for Iodine (I₂). Chlorine oxidizes I^- to I₂, which dissolves in CHCl₃ with a violet/purple color.
- Molar mass calculations:
Atomic weight of I = 127 Molar mass of AgI = 108 (Ag) + 127 (I) = 235 g mol⁻¹. (Since Ag is not provided in data, assume standard 108. The PDF explicitly uses 235).
Step 1: Apply Carius Method Formula
Given: Mass of organic compound (w) = 0.15 g Mass of AgI precipitate (m) = 0.12 g
% of I = (127)/(235) × (0.12)/(0.15) × 100 % of I = (127)/(235) × 0.8 × 100 % of I = 0.5404 × 80 = 43.234%Step 2: Rounding
The nearest integer to 43.23 is 43.
Pattern Recognition
Always use the qualitative test (chloroform layer color) to definitively identify the halogen before executing the quantitative Carius formula.
Chapter Mix
Class 11 Chemistry: Organic Chemistry Some Basic Principles and Techniques