Which can show the cis-trans isomerism ?A ClCH2CH2Cl B Cl2C=CH2 C Cl2C=CCl2 D ClCH=CHCl

To determine which compound can show cis-trans isomerism, we need to examine the presence of double bonds and the arrangement of substituents around those double bonds.

A. ClCH2CH2Cl: This compound does not have a double bond, so it cannot exhibit cis-trans isomerism.

B. Cl2C=CH2: This compound has a double bond between the carbon atoms. However, there are no substituents on either side of the double bond, so it cannot show cis-trans isomerism.

C. Cl2C=CCl2: This compound also has a double bond between the carbon atoms. Additionally, there are two chlorine atoms on one side of the double bond and two chlorine atoms on the other side. This arrangement allows for cis-trans isomerism.

D. ClCH=CHCl: This compound has a double bond between the carbon atoms. However, there is only one chlorine atom on each side of the double bond, so it cannot exhibit cis-trans isomerism.

Therefore, the compound that can show cis-trans isomerism is C. Cl2C=CCl2.