Question

Given below are two statements:
Statement I: Ozonolysis followed by treatment with Zn, H$_2$O of cis-2-butene gives ethanal.
Statement II: The product obtained by ozonolysis followed by treatment with Zn, H$_2$O of 3, 6-dimethyloct-4-ene has no chiral carbon atom.
In the light of the above statements, choose the correct answer from the options given below.

• A. Both Statement I and Statement II are true
• B. Statement I is false but Statement II is true
• C. Statement I is true but Statement II is false
• D. Both Statement I and Statement II are false

Hint:

For ozonolysis, always check the symmetry of the reactant molecule. Symmetrical cleavage products will not have chiral centers, while asymmetrical products will have chiral centers.

Answer 1

The Correct Option is C

Step 1: Analyze Statement I
Ozonolysis is a reaction in which an alkene is cleaved by ozone (\( \text{O}_3 \)) to form an ozonide intermediate. Subsequent reduction of this ozonide by zinc (\( \text{Zn} \)) and water (\( \text{H}_2 \text{O} \)) yields two carbonyl compounds. For cis-2-butene, the reaction is depicted as: \[ \text{cis-2-butene} \xrightarrow{O_3} \text{ozonide intermediate} \xrightarrow{Zn, H_2O} \text{ethanal (acetaldehyde)}. \] The symmetrical cleavage of the double bond in cis-2-butene upon ozonolysis results in two molecules of ethanal (acetaldehyde), a simple aldehyde. Consequently, Statement I is true
. 
Step 2: Analyze Statement II
Ozonolysis of \(\textit{3, 6-dimethyloct-4-ene}\) followed by treatment with \( \text{Zn} \) and \( \text{H}_2 \text{O} \) cleaves the double bond, generating two products. The symmetry of the molecule is crucial. 3, 6-dimethyloct-4-ene is symmetrical, and its double bond cleavage produces two carbonyl groups. The resulting product is symmetrical, meaning it will not possess any chiral centers as both resultant products are achiral and identical. In essence, the two derived products are symmetrical and lack chiral centers, rendering Statement II false.