JEE Main · 2022 · 28 Jun 2022 · Shift 1 · Practical and Analytical Chemistry

In Carius method for halogen estimation, the organic compound is heated with fuming nitric acid and silver nitrate. All bromine is converted to AgBr.

Molar mass of AgBr = 108 + 80 = 188 g/mol

Moles of AgBr formed = $\frac{0.40}{188}$ mol

Since each AgBr contains one Br atom:
Moles of Br = $\frac{0.40}{188}$ mol

Mass of Br = $\frac{0.40}{188}\times 80$ g

Percentage of Br = $\frac{\frac{0.40\times 80}{188}}{0.5}\times 100=\frac{0.40\times 80\times 100}{188\times 0.5}=\frac{3200}{94}=34.04\%$

Nearest integer: 34