Identify the correct statements for Ethylene dichloride and Ethylidene chloride
(A) They represent structural isomers.
(B) Both are formed by reaction of ethene with chlorine in presence of $CCl_4$
(C) Both the compounds belong to a class of dihalocompounds
(D) Both the compounds are optically inactive.
Choose the correct answer from the options given below.
Answer & explanation
Correct answer: option 1
The correct answer is Option (1) → (A), (C) and (D) only
Detailed Explanation
First understand the two compounds:
Ethylene dichloride = 1,2–dichloroethane
Structure: Cl–CH₂–CH₂–Cl
Ethylidene chloride = 1,1–dichloroethane
Structure: CH₃–CHCl₂
Both have the same molecular formula:
C₂H₄Cl₂
But the position of chlorine atoms is different.
Statement (A): They represent structural isomers
Structural isomers have:
Same molecular formula
Different connectivity of atoms
In ethylene dichloride → Chlorine atoms are on two different carbon atoms
In ethylidene chloride → Both chlorine atoms are on the same carbon atom
Since their structures are different but formula is same, they are positional (structural) isomers.
Therefore Statement (A) is correct.
Statement (B): Both are formed by reaction of ethene with chlorine in presence of CCl₄
Ethene + Cl₂ in inert solvent (like CCl₄) undergoes addition reaction:
CH₂=CH₂ + Cl₂ → Cl–CH₂–CH₂–Cl
This forms only 1,2–dichloroethane (ethylene dichloride)
Ethylidene chloride (1,1–dichloroethane) is NOT formed by this reaction.
It is prepared by chlorination of ethane or via other substitution pathways.
Therefore Statement (B) is incorrect.
Statement (C): Both the compounds belong to a class of dihalocompounds
Dihalo compounds contain two halogen atoms.
Both contain two chlorine atoms.
Ethylene dichloride → vicinal dihalide (on adjacent carbons)
Ethylidene chloride → geminal dihalide (on same carbon)
Hence both belong to dihalocompounds.
Therefore Statement (C) is correct.
Statement (D): Both the compounds are optically inactive
Optical activity requires a chiral carbon (carbon with four different groups).
Ethylene dichloride:
Cl–CH₂–CH₂–Cl
No carbon has four different substituents
Symmetrical molecule
Optically inactive
Ethylidene chloride:
CH₃–CHCl₂
The second carbon has:
Cl
Cl
H
CH₃
Two identical groups (Cl, Cl) are present
Hence not chiral
Therefore optically inactive.
Statement (D) is correct.