Question

An optically active alkene having molecular formula C$_8$H$_{16$ gives acetone as one of the products on ozonolysis. The structure of the alkene is} 

• A. Option a
• B. Option b
• C. Option c
• D. Option d

Hint:

Ozonolysis shortcuts:

 Acetone $\Rightarrow$ (CH$_3$)$_2$C= fragment present

 Check symmetry for optical activity

 Chiral alkene must lack internal symmetry 

Answer 1

The Correct Option is B

Concept: Ozonolysis cleaves C=C bond into carbonyl compounds:
\[ \text{C=C} \xrightarrow{\text{O}_3} \text{ketones/aldehydes} \]
If acetone forms, one side of alkene must contain:
\[ \text{C(CH}_3)_2= \]
Also, molecule must be optically active \( \Rightarrow \) chiral center present.
Step 1: Requirement for acetone formation
Acetone forms when double bond carbon has:
\[ \text{two CH}_3 \text{ groups} \]
Thus alkene must contain:
\[ (\text{CH}_3)_2\text{C=} \]
Step 2: Optical activity condition
Must contain chiral carbon
No internal plane of symmetry
Among options, only (B) contains:
Isopropylidene unit (gives acetone)
Adjacent stereogenic center
Conclusion:
Structure (B) satisfies both ozonolysis and chirality conditions.