Question

Assertion :

$(C{H}_3-\underset{Cl}{\underset{|}{CH}}-CH=CH-\underset{Cl}{\underset{|}{CH}}-C{H}_3)$

The cis form exists in three - diastereomers. Reason: One forms is optically inactive due to the presence of centre of symmetry.

• A. Both Assertion and Reason are correct and Reason is the correct explanation for Assertion
• B. Both Assertion and Reason are correct but Reason is not the correct explanation for Assertion
• C. Assertion is correct but Reason is incorrect
• D. Both Assertion and Reason are incorrect

Answer 1

The correct option is C Assertion is correct but Reason is incorrect

$\begin{array}{c}\text{1,2 are chiral carbons.}\\ \text{In cis form if the configuration at two chiral}\\ \text{carbons are}(R,S);(R,R)\text{;}(S,S)\text{they are diastereomers}\end{array}$

$\begin{array}{c}\text{Therefore there are three diastereomer's and}\\ \text{none is optically inactive due to centre of symmetry}\end{array}$