Alkenes

The product of given reaction will be according to Markownikoff's rule, this is because peroxide effect is applicable only in case of and not effective in case of .

We need to find an alkene that meets three criteria: (A) Molecular formula is C₈H₁₆. (B) Gives acetone (CH₃COCH₃) upon ozonolysis (followed by reductive workup, usually implied). (C) Is optically active (possesses a chiral center and is not a meso compound). Let's analyze each option:

• (A) 2,3-Dimethylhex-2-ene:
  Formula: C₈H₁₆ (Correct).
  Ozonolysis: Cleaves the double bond. C(CH₃)₂= gives acetone. =C(CH₃)CH₂CH₂CH₃ gives 2-pentanone. So, it yields acetone.
  Optical Activity: No chiral center. Carbon atoms are either sp² hybridized or have two identical groups attached (e.g., CH₃ groups on C2, H atoms on CH₂s). It is optically inactive.
• (B) 3,4-Dimethylhex-2-ene:
  Formula: C₈H₁₆ (Correct).
  Ozonolysis: C(CH₃)₂= gives acetone. =CHCH(CH₃)C₂H₅ gives 3-methylpentan-2-al. So, it yields acetone.
  Optical Activity: The carbon atom at position 4 (C4) is bonded to four different groups: H, CH₃, C₂H₅ (ethyl), and the C=CH(C(CH₃)₂) group.
  Thus, C4 is a chiral center. The molecule is optically active.
• (C) 3,4-Dimethylhex-3-ene:
  Formula: C₈H₁₆ (Correct).
  Ozonolysis: Cleaves the double bond. C(C₂H₅)(H)= gives propanal. =C(CH₃)CH(CH₃)₂ gives 3-methylbutan-2-one. Does not yield acetone.
• (D) 3-Ethyl-2-methylpent-2-ene:
  Formula: C₈H₁₆ (Correct).
  Ozonolysis: C(CH₃)₂= gives acetone. =C(C₂H₅)₂ gives 3-pentanone. So, it yields acetone.
  Optical Activity: No chiral center. The molecule is optically inactive.

Only option (B) satisfies all three conditions: has the formula C₈H₁₆, yields acetone upon ozonolysis, and is optically active due to the chiral center at C4.