What is the missing reagent in the reaction below?
A)I
B)II
C)III
D)IV

Question

What is the missing reagent in the reaction below? 
A)I 
B)II 
C)III 
D)IV

Quizplus · Accepted Answer

The reaction appears to be a substitution reaction where an alkyl group is being substituted with a halogen atom. The starting material is 2-butanol, which has an -OH group. For a substitution reaction to occur, the -OH group needs to be converted to a good leaving group. This is achieved using a reagent such as phosphorus tribromide (PBr3) or thionyl chloride (SOCl2). In the given reaction, only III (PBr3) is a reagent that can convert the -OH group to a good leaving group (Br) and facilitate substitution. Therefore, the best choice is C.

What Is the Missing Reagent in the Reaction Below