CUET Preparation Today
Case: Read the passage and answer the questions There are several methods to prepare halo alkanes and haloarenes. One of the methods is to prepare from alcohol. The hydroxyl group of an alcohol is replaced by halogen on reaction with concentrated halogen acids, phosphorus halides or thionyl chloride. The halo alkanes are prepared by treating alkane with a limited amount of halogen in presence of halogen carrier and sunlight or heat. Adding hydrogen halide to alkene also results in the formation of halo alkanes. Haloarenes are prepared from hydrocarbons by electrophilic substitution and amines by Sandmeyer’s reaction. |
| What type of reaction is bromination of methane in presence of sunlight? |
Free radical substitution Nucleophilic substitution Electrophilic substitution None of the above |
| Free radical substitution |
| This reaction between methane and bromine happens in the presence of ultraviolet light - typically sunlight. This is a good example of a photochemical reaction - a reaction brought about by light. |
