In the estimation of halogen, 0.25 g of an organic compound gave 0.13 g of silver bromide. What is the percentage of bromine in the compound? 

0.25 g of organic compound gives 0.13 g of silver bromide. Percentage of Br is calculated as:

$$\begin{gathered} \%\mathrm{Br}=\frac{\mathrm{Atomic} \mathrm{weight} \mathrm{of} \mathrm{Br}}{\mathrm{Molecular} \mathrm{weight} \mathrm{of} \mathrm{AgBr}}\times \frac{\mathrm{Mass} \mathrm{of} \mathrm{AgBr}}{\mathrm{Mass} \mathrm{of} \mathrm{organic} \mathrm{compound}} \\ =\frac{80}{188}\times \frac{0.13}{0.25}\times 100=22.13\% \end{gathered}$$