In each reaction box, place the best reagent from the list below. draw the intermediate compound.

Reagent A: PBr₃

Reagent B: Mg in Et₂O.

Explanation:

Hello,

In this case, your facing a problem in which a carboxylic acid is produced starting by an alcohol. More specifically, cyclopentanol must react with phosphorous tribromide in order to yield bromocyclopentane which is more likely to produce a carboxylic acid, therefore, reagent A is PBr₃.

On the other hand, by means of the production of the specified product, bromocyclopentane must react with carbon dioxide and magnesium in diethyl ether in acidic media to promote the production of the cyclopentanoic acid via the grignard reaction (substitution of the bromine by the carboxyle group), therefore, reagent B is Mg in Et₂O.

Best regards.

i think it's c. if you look search electronic symbol on google and then click on wiki it shows you a