Question

which among the following will not decolourise br2+ ccl4
1)pentene
2.cyclohexane
3.pentyne
4.cyclohexene​

Answer 1

Basic Concept:

=> Bromine is a strong oxidizing agent, it reacts readily with unsaturated compounds in a reaction called halogenation to form addition products.

=> In this process, the reddish-brown colour of bromine discharges or it is decolourised.

=> So, it reacts with alkenes, alkynes, cycloalkenes and cycloalkynes (Unsaturated compounds) to give a saturated addition product.

Solution:

=> Thus, Bromine dissolved in CCl4 will not decolourise 2)Cyclohexane, as this is an alkane or a saturated compound that cannot undergo addition.