Suggest a synthesis for each of the following, using nitrobenzene and any other necessary reagents. (a) \(\mathrm{C}_{6} \mathrm{H}_{5} \mathrm{~N}=\mathrm{NC}_{6} \mathrm{H}_{5}\) (c) \(\mathrm{p}-\mathrm{CH}_{3} \mathrm{C}_{6} \mathrm{H}_{4} \mathrm{NH}_{2}\) (b) \(\mathrm{C}_{6} \mathrm{H}_{5} \mathrm{NHOH}\) (d) \(\mathrm{C}_{6} \mathrm{H}_{5} \mathrm{ND}_{2}\)

(a) To synthesize Azobenzene (\(\mathrm{C}_{6} \mathrm{H}_{5} \mathrm{~N}=\mathrm{NC}_{6} \mathrm{H}_{5}\)), follow these steps: 1. Reduce nitrobenzene to aniline (\(\mathrm{C}_{6} \mathrm{H}_{5} \mathrm{NH}_{2}\)) using \(\mathrm{Sn}/\mathrm{HCl}\). 2. Form diazonium salt (\(\mathrm{C}_{6} \mathrm{H}_{5} \mathrm{N}_{2}^{+} \mathrm{Cl}^{-}\)) with nitrous acid (\(\mathrm{HNO}_2\)) using sodium nitrite (\(\mathrm{NaNO}_2\)) and hydrochloric acid (\(\mathrm{HCl}\)). 3. Perform coupling reaction with another equivalent of aniline to produce azobenzene. (c) To synthesize p-Toluidine (\(\mathrm{p}-\mathrm{CH}_{3} \mathrm{C}_{6} \mathrm{H}_{4} \mathrm{NH}_{2}\)): 1. Nitrate nitrobenzene to obtain 1,3-dinitrobenzene using a mixture of \(\mathrm{HNO}_3\) and \(\mathrm{H}_{2} \mathrm{SO}_{4}\). 2. Reduce 1,3-dinitrobenzene to 3-nitroaniline using \(\mathrm{Fe}/\mathrm{HCl}\). 3. Alkylate 3-nitroaniline using methyl chloride (\(\mathrm{CH}_{3} \mathrm{Cl}\)) and \(\mathrm{AlCl}_3\) (Friedel-Crafts Alkylation) to obtain p-toluidine. (b) To synthesize Phenylhydroxylamine (\(\mathrm{C}_{6} \mathrm{H}_{5} \mathrm{NHOH}\)): 1. Partially reduce nitrobenzene to nitrosobenzene (\(\mathrm{C}_6\mathrm{H}_5\mathrm{NO}\)) using \(\mathrm{Zn}/\mathrm{HCl}\). 2. Reduce nitrosobenzene with lithium aluminum hydride (\(\mathrm{LiAlH}_4\)) in THF to obtain phenylhydroxylamine. (d) To synthesize Benzene-d2-amine (\(\mathrm{C}_{6} \mathrm{H}_{5} \mathrm{ND}_{2}\)): 1. Reduce nitrobenzene to aniline (\(\mathrm{C}_{6} \mathrm{H}_{5} \mathrm{NH}_{2}\)) using \(\mathrm{Sn}/\mathrm{HCl}\). 2. Replace N-H with N-D using deuterium and a transition metal catalyst, such as palladium/carbon (\(\mathrm{Pd/C}\)), to yield benzene-d2-amine.