Question

Convert 1-Bromopropane to 2-Bromopropane?

Answer 1

The Dehydrohaogenation of 1-bromo propane with alcoholic KOH gives propene which on again hydrohalogenation with HBr gives 2-bromo propane due to Markonikove's rule for addition.

Answer 2

ch3-ch2-ch2-br→ch3-ch=ch2→ch3-ch-ch3
 1-bromopropane                                 l            
                                                              br      
                                                       2-bromopropane
first we perform dehydrohalogenation for 1-bromoprapane then we get 1-propene 
for 1-propene, by markonikoff addition rule we add HBr to 1-propene we finally get 2-bromopropane