Propose a synthesis for Br starting with benzene NO₂

you want to synthesize butanoic acid you have propyl bromide, magnesium, and carbon dioxide. draw the reaction scheme - how would we design this reaction?

An unknown compound is treated with peroxyacetic acid in dilute sulfuric acid.  The product of reaction 1 is reacted with excess PBr3 , then excess NaNH2 (reaction 3).  The product of reaction 3 is treated with lithium, then n-butylbromide (reaction 4).  In reaction 5 the product of reaction 4 is reacted with ozone, then NaHSO3.  This final reaction produced 2 acids, propanoic acid and pentanoic acid.  What was the original unknown compouond?

27) Give the products of the reaction and provide a step-by-step mechanism for the formation of the products. O not + H₂O HCI