C6H5N2Cl + C2H5OH → ? C6H5NH2 + Br2(aq) → ? Explain ammonolysis of alkyl ..

These questions cover various reactions and concepts related to aromatic amines, nitriles, and amines in general.

Question 1: Reaction of C6H5N2Cl with C2H5OH

Solution:

This is a diazonium salt reaction with ethanol (C2H5OH).

• C6H5N2Cl is benzenediazonium chloride.
• When treated with ethanol, it undergoes replacement of the diazonium group by an ethoxy group.

Reaction: C6​H5​N2​Cl+C2​H5​OH→C6​H5​OC2​H5​+N2​+HCl

Product: Ethoxybenzene (phenetole).

Question 2: Reaction of C6H5NH2 with Br2(aq)

Solution:

This is the bromination of aniline in aqueous bromine.

• Aniline (C6H5NH2) reacts with bromine water to give 2,4,6-tribromoaniline due to activating effect of -NH2 group.

Reaction: C6​H5​NH2​+3Br2​aq​C6​H2​Br3​NH2​+3HBr

Product: 2,4,6-tribromoaniline (white precipitate).

Question 3: Explain ammonolysis of alkyl halide

Solution:

Ammonolysis is the reaction of alkyl halides with ammonia to form amines.

• Alkyl halide (R-X) reacts with excess ammonia (NH3).
• Nucleophilic substitution occurs, replacing halogen with -NH2 group.
• Primary amine is formed initially, but further reaction can give secondary, tertiary amines and quaternary ammonium salts.

General reaction: R−X+NH3​→R−NH2​+HX

Question 4: Identify A & B in the reaction sequence

CH3​−C≡NNa/C2​H5​OH​ANaNO2​/dil.HCl​B

Solution:

• Step 1: Reduction of nitrile (CH3-C≡N) with sodium in ethanol reduces nitrile to an imine salt, which hydrolyzes to give a primary amine.

So, A = CH3-CH2-NH2 (ethylamine)

• Step 2: Reaction of primary amine with NaNO2 and dilute HCl forms diazonium salt.

So, B = CH3-CH2-N2+ Cl- (ethyl diazonium chloride)

Question 5: Predict product of Nitrobenzene with Sn/conc.HCl

Solution:

• Nitrobenzene is reduced to aniline by Sn and concentrated HCl.

Reaction: C6​H5​NO2​Sn/conc.HCl​C6​H5​NH2​

Product: Aniline

Question 6: Identify A & B in the reaction sequence

C6​H5​CH2​Bralco/KCN​ANaI/ethanol​B

Solution:

• Step 1: Benzyl bromide reacts with alcoholic KCN to give benzyl cyanide (C6H5CH2CN) by nucleophilic substitution.

So, A = C6H5CH2CN (benzyl cyanide)

• Step 2: Benzyl cyanide reacts with NaI in ethanol, where iodide ion replaces the cyanide group by nucleophilic substitution.

So, B = C6H5CH2I (benzyl iodide)

Question 7: Explain Gabriel phthalimide synthesis

Solution:

Gabriel phthalimide synthesis is a method to prepare primary amines.

• Phthalimide is treated with KOH to form potassium phthalimide.
• It reacts with alkyl halide (R-X) to give N-alkyl phthalimide.
• Hydrolysis (acidic or basic) of N-alkyl phthalimide yields primary amine (R-NH2).

Advantages:

• Produces only primary amines without contamination by secondary or tertiary amines.

Question 8: What are amines? How are they classified?

Solution:

• Amines are organic derivatives of ammonia (NH3) where one or more hydrogen atoms are replaced by alkyl or aryl groups.

Classification:

1. Based on number of alkyl/aryl groups attached to nitrogen:

   • Primary amine (1°): R-NH2
   • Secondary amine (2°): R2-NH
   • Tertiary amine (3°): R3-N

2. Based on structure:

   • Aliphatic amines: Alkyl groups attached
   • Aromatic amines: Aryl groups attached (e.g., aniline)

3. Based on basicity:

   • Primary, secondary, tertiary amines differ in basic strength due to electronic and steric effects.