Alkenes

Step 1: Understanding ozonolysis.
Ozonolysis of an alkene ( ) breaks the double bond to form two carbonyl compounds. Reduction with zinc dust and water leads to the formation of ketones or aldehydes. In this case, the ozonolysis followed by reduction of an alkene results in propanone.
Step 2: Analyzing the options.
(A) Butanal: Incorrect. Butanal is an aldehyde, but not the product of this reaction.
(B) Propanal: Incorrect. Propanal is an aldehyde, but it is not the product of this reaction.
(C) Propanone: Correct — Propanone is the product formed from the ozonolysis and reduction of a specific alkene.
(D) Butanone: Incorrect. Butanone is a ketone, but it is not the product of this reaction.
Step 3: Conclusion.
The correct answer is (C) Propanone, which is the product obtained from ozonolysis followed by reduction.

Step 1: Understanding the reaction.
The reaction of alkyl halides with sodium metal in dry ether is a Wurtz reaction. This reaction leads to the formation of alkanes by the coupling of two alkyl radicals. For 2,5-dimethylhexane to form, the reactant must have the correct structure. Isobutyl bromide ( ) leads to the formation of 2,5-dimethylhexane upon undergoing the Wurtz reaction.
Step 2: Analyzing the options.
(A) tert-butyl bromide: Incorrect. The reaction of tert-butyl bromide would produce a highly branched alkane, not 2,5-dimethylhexane.
(B) sec-butyl bromide: Incorrect. sec-Butyl bromide would lead to a different alkane, not 2,5-dimethylhexane.
(C) n-butyl bromide: Incorrect. n-Butyl bromide would not give the desired dimethyl-substituted product.
(D) isobutyl bromide: Correct — Isobutyl bromide produces 2,5-dimethylhexane via the Wurtz reaction.
Step 3: Conclusion.
The correct answer is (D) isobutyl bromide, which gives 2,5-dimethylhexane on reaction with sodium in dry ether.

Step 1: Understanding the reaction mechanism.
The addition of hydrogen bromide (HBr) to alkenes follows Markovnikov's rule. In the case of but-2-ene, the addition of HBr leads to the formation of 2-bromobutane, as the bromine attaches to the carbon with more alkyl groups (which is more substituted). For but-1-ene, 2-bromobutane is also formed.
Step 2: Analyzing the options.
(A) 1-bromobutane and 2-bromobutane respectively: Incorrect. This is not the correct order of products.
(B) 1-bromobutane only: Incorrect. This product is not obtained in either case.
(C) 2-bromobutane and 1-bromobutane respectively: Incorrect. The correct product is 2-bromobutane, not 1-bromobutane.
(D) 2-bromobutane only: Correct — Both but-2-ene and but-1-ene lead to the formation of 2-bromobutane after the addition of HBr.
Step 3: Conclusion.
The correct answer is (D) 2-bromobutane only, as the product of both reactions is 2-bromobutane.

Step 1: Nature of reaction.
Hot, acidic potassium permanganate is a strong oxidising agent and causes oxidative cleavage of carbon–carbon double bonds.

Step 2: Oxidation of cyclohexene.
Cyclohexene undergoes oxidative cleavage of the double bond, leading to ring opening and formation of a dicarboxylic acid.

Step 3: Product formation.
The six-membered ring of cyclohexene is converted into hexanedioic acid, commonly known as adipic acid.

Step 4: Conclusion.
Therefore, the compound that forms adipic acid is Cyclohexene.