Question

Using the Mulliken-barker test how the nitro group is detected?

Answer 1

Mulliken-barker test:

• The Mulliken-barker test is used for detecting the nitro group in the compound.
• In the Mulliken barker test, the nitro group$(-\mathrm{N}{\mathrm{O}}_2)$is reduced to hydroxylamine$\left({\mathrm{NH}}_2\mathrm{OH}\right)$ in the presence of a neutral reducing agent.
• The Nitro group is detected by the silver-mirror appearance that appears at the end of the reaction.
• Hydroxylamine is further heated with Tollen’s reagent $\left(\right[\mathrm{Ag}(\mathrm{N}{\mathrm{H}}_3{)}_2\left]\mathrm{OH}\right)$. On heating, hydroxylamine gets oxidized to the respective nitroso compound and the Tollen’s reagent is reduced to metallic silver.

The reaction of nitrobenzene with nitrosobenzene is depicted below: