Question

The major product Z formed in the following sequence of reactions is:  

$$ {C2H5Cl →[AgNO2] X →[Sn/HCl] Y →[(i)\ NaNO2][(ii)\ HCl,\ H2O] Z} $$

• A. \({C2H5NO2}\)
• B. \({C2H5-N=N-OH}\)
• C. \({C2H5NH2}\)
• D. \({C2H5OH}\)

Hint:

Alkyl halide with \(AgNO_2\) gives nitroalkane, nitroalkane on reduction gives amine, and primary aliphatic amine with nitrous acid gives alcohol.

Answer 1

The Correct Option is D

Let's analyze the given sequence of reactions and determine the major product \( Z \).

1. Start with the initial reactant \({C2H5Cl}\).
2. The first reaction involves treatment with \(\text{AgNO}_2\). This reaction typically allows for the substitution of the chlorine atom with a nitro group, forming nitroethane (\({C2H5NO2}\)):

\({C2H5Cl + AgNO2 \rightarrow C2H5NO2 + AgCl}\)

1. The product is identified as \(X = \text{nitroethane}\).
2. In the second step, nitroethane (\(X\)) is reduced using \(\text{Sn/HCl}\), converting the nitro group to an amine. This results in the formation of ethylamine (\({C2H5NH2}\)):

\({C2H5NO2 \overset{Sn/HCl}{\longrightarrow} C2H5NH2}\)

1. The product is identified as \(Y = \text{ethylamine}\).
2. The third step involves converting the ethylamine (\(Y\)) to a diazonium salt using \(\text{NaNO}_2\) and \(\text{HCl/H}_2\text{O}\), followed by hydrolysis. This results in the formation of ethanol (\({C2H5OH}\)):

\({C2H5NH2 \overset{NaNO2/HCl,H2O}{\longrightarrow} C2H5OH}\)

1. The final product is identified as \(Z = \text{ethanol}\).

Therefore, the major product \(Z\) formed in the given sequence of reactions is ethanol (\({C2H5OH}\)).

Justification of Options:

• Option 1 (\(C2H5NO2\)): This is the intermediate product after the first step, not the final product.
• Option 2 (\(C2H5-N=N-OH\)): A diazo compound is not formed in this sequence.
• Option 3 (\(C2H5NH2\)): This is the intermediate product after the second step, not the final product.
• Option 4 (\(C2H5OH\)): This is the correct final product as justified by the steps above.

Hence, the correct answer is: \({C2H5OH}\)