Incorrect method of preparation for alcohols from the following is:

Solution

Chemistry ma’am · 3 steps

Ask what each reaction puts on carbon: three give an –OH, ozonolysis only gives a C=O.

1. What we need. A method that prepares alcohols must end with an -OH group on an sp³ carbon. Check each option for the product it actually gives.

   Option	What happens	Product	Gives alcohol?
   (a) Hydroboration-oxidation	BH₃ adds across C=C, then H₂O₂/OH⁻ swaps B for OH	anti-Markovnikov alcohol	yes
   (b) Ketone + RMgBr, then H₃O⁺	R adds to the carbonyl carbon, then O is protonated	tertiary alcohol	yes
   (c) Ozonolysis	O₃ cleaves the C=C completely, then Zn/H₂O works up the ozonide	aldehydes and/or ketones	no
   (d) R–X + aqueous NaOH	OH⁻ replaces the halogen by substitution	alcohol	yes

2. Why ozonolysis fails. Ozone breaks the double bond into two pieces, and each former alkene carbon becomes a C=O carbon. You get carbonyl compounds, not alcohols. Reducing them to alcohols would need a separate step such as NaBH₄.
3. So. Ozonolysis of an alkene is the incorrect method, so the answer is (c).

The idea to keep. To check a preparation, write the product it actually forms. Ozonolysis cuts a C=C into carbonyl compounds, so it gives aldehydes or ketones, never alcohols directly.

Answer from the NTA final answer key. Solution by PrepWiser.