Question

Identify 'Y' in the following reaction sequence: CH₂ = CH₂ [(ii) Zn/H₂O](i) O₃ X NH₃ Y

• A. Hexamethylene tetramine
• B. Formaldehyde
• C. Oxime
• D. Diacetone ammonia

Hint:

While formaldehyde gives Urotropine with ammonia, acetaldehyde reacts to give acetaldehyde ammonia (an addition product), and acetone gives diacetone ammonia (a condensation product).

Answer 1

The Correct Option is A

Concept: This sequence involves the reductive ozonolysis of an alkene followed by the reaction of the resulting carbonyl compound with ammonia. Key reactions: • Ozonolysis: Cleavage of the C=C double bond to form carbonyl compounds. • Ammonia Reaction: Specific aldehydes like formaldehyde react with ammonia to form complex cyclic structures.
Ethene (CH₂=CH₂) reacts with ozone (O₃) followed by reduction with Zinc and water (Zn/H₂O). This breaks the double bond and adds an oxygen atom to each carbon: CH₂ = CH₂ O₃, Zn/H₂O 2HCHO Thus, 'X' is Formaldehyde (Methanal).
Formaldehyde (HCHO) reacts uniquely with Ammonia (NH₃). Unlike other aldehydes which form imines or aldehyde ammonias, 6 molecules of formaldehyde react with 4 molecules of ammonia to form a crystalline solid called Hexamethylene tetramine (also known as Urotropine): 6HCHO + 4NH₃ (CH₂)₆N₄ + 6H₂O This compound is used medically as a urinary antiseptic.