Question

The correct statements about the products B and C in the given reactions are (Ethanol reacts with HCl/Anhy ZnCl$_2$ to give A. A reacts with ethanolic AgCN to give B (Minor) and C (Major)). I. B and C are functional isomers II. With H$_2$|Catalyst B gives 1$^\circ$ amine and C gives 2$^\circ$ amine III. B on acid hydrolysis gives formic acid and C gives C$_3$H$_6$O$_2$ IV. C forms isocyanate with HgO

• A. I & III
• B. II & III
• C. I, II & IV
• D. II, III & IV

Hint:

Remember the reactivity of ambident nucleophiles like CN$^-$. - With ionic cyanides (KCN, NaCN), the attack is primarily through carbon, forming nitriles (R-CN) as the major product. - With covalent cyanides (AgCN), the attack is primarily through nitrogen, forming isocyanides (R-NC) as the major product. Also, remember the distinct hydrolysis and reduction products of nitriles and isocyanides.

Answer 1

The Correct Option is C

Step 1: Identify products A, B, and C.
Reaction 1: CH$_3$CH$_2$OH (Ethanol) + HCl $\xrightarrow{\text{Anhy. ZnCl}_2}$ A
- This is the Lucas test reaction (nucleophilic substitution, -OH replaced by -Cl).
- A = CH$_3$CH$_2$Cl (Ethyl chloride)
Reaction 2: CH$_3$CH$_2$Cl (A) + ethanolic AgCN $\rightarrow$ B (Minor) + C (Major)
- AgCN is covalent; N atom attacks the ethyl group, forming isocyanide as major product.
- Minor product forms via C-attack forming nitrile.
- B (Minor) = CH$_3$CH$_2$CN (Propionitrile)
- C (Major) = CH$_3$CH$_2$NC (Ethyl isocyanide)
Step 2: Evaluate statements about B and C.
I. B and C are functional isomers:
- B is a nitrile (R-CN), C is an isocyanide (R-NC).
- Same molecular formula (C$_3$H$_5$N) but different functional groups.
- Correct statement.
II. With H$_2$|Catalyst, B gives 1$^\circ$ amine and C gives 2$^\circ$ amine:
- Reduction of B: CH$_3$CH$_2$CN + 2H$_2 \xrightarrow{\text{Catalyst}}$ CH$_3$CH$_2$CH$_2$NH$_2$ (Primary amine)
- Reduction of C: CH$_3$CH$_2$NC + 2H$_2 \xrightarrow{\text{Catalyst}}$ CH$_3$CH$_2$NHCH$_3$ (Secondary amine)
- Correct statement.
III. B on acid hydrolysis gives formic acid and C gives C$_3$H$_6$O$_2$:
- Hydrolysis of B: CH$_3$CH$_2$CN + 2H$_2$O + H$^+$ $\rightarrow$ CH$_3$CH$_2$COOH (Propanoic acid) + NH$_4^+$
- Hydrolysis of C: CH$_3$CH$_2$NC + 2H$_2$O + H$^+$ $\rightarrow$ CH$_3$CH$_2$NH$_2$ + HCOOH (Formic acid)
- Statement is reversed, so incorrect.
IV. C forms isocyanate with HgO:
- CH$_3$CH$_2$NC + HgO $\rightarrow$ CH$_3$CH$_2$NCO (Ethyl isocyanate) + Hg
- Correct statement.