Question

The following two reactions give the same foul smelling product \(Z\):

\[ {C2H5CONH2 →[Br2/NaOH] X} \] \[ {X →[CHCl3/alcoholic\ KOH][\Delta] Z} \] \(X\) and \(Z\), respectively, are:

• A. \(X={C2H5CN},\ Z={C2H5NC}\)
• B. \(X={C2H5NH2},\ Z={C2H5CN}\)
• C. \(X={C2H5NH2},\ Z={C2H5NC}\)
• D. \(X={CH3NH2},\ Z={CH3NC}\)

Hint:

Hofmann bromamide reaction converts amide into amine with one carbon less, and carbylamine reaction converts primary amine into foul-smelling isocyanide.

Answer 1

The Correct Option is C

Step 1: Identify the first reaction.  

The first reaction is: $$ C_2H_5CONH_2 \rightarrow[Br_2/NaOH] X $$ This is Hofmann bromamide degradation reaction. 
In this reaction, an amide gives a primary amine with one carbon atom less. 


Step 2: Apply Hofmann degradation. 

The given amide is: $$ C_2H_5CONH_2 $$ This is propanamide. 
After Hofmann degradation, it gives: $$ C_2H_5NH_2 $$ Therefore: X = C₂H₅NH₂ 


Step 3: Identify the second reaction. 

The second reaction is: $$ X \rightarrow[CHCl_3/alcoholic\ KOH,\ \Delta] Z $$ Primary amines react with chloroform and alcoholic KOH to form isocyanides. 
This is called the carbylamine reaction. 


Step 4: Apply carbylamine reaction. 

Since: $$ X = C_2H_5NH_2 $$ It gives: $$ C_2H_5NC $$ Therefore: Z = C₂H₅NC 


Step 5: Final answer. 

X = C₂H₅NH₂
Z = C₂H₅NC