Question

$1.23$ g of nitrobenzene on reduction with $Zn+N{H}_{4}Cl$ gives N-phenyl hydroxyl amine that is isomerised to 4-amino phenol. Thus, the number of electrons involved and the element reduced are respectively :

• A. $24\times {10}^{21},N$
• B. $24\times {10}^{23},N$
• C. $12\times {10}^{23},N$
• D. $6\times {10}^{23},N$

Answer 1

Answer: (A)

$24\times {10}^{21},N$

$Ar-\underset{+3}{N}{O}_2+4e^{-}\to Ar-\underset{-1}{N}H-OH$

Change in oxidation state of Nitrogen in the reaction is $-4$.

$1$ mol ($123$ g) of nitrobenzene requires $4N_a$ electrons where $N_a$ is the Avogadro number.

$1.23$ g ($0.01$ mol) of nitrobenzene will require $0.01\times 4\times 6.023\times {10}^{23}=24\times {10}^{21}$ electrons.

During the reaction, nitrogen is reduced.