Answer: 1,1-dichloroethane.
- A 1,2-dichloroethane
- B 1,3-dichloropropane
- C 1,1-dichloroethane
- D 1,4-dichlorobutane
Correct answer: C. 1,1-dichloroethane
Explanation: In 1,1-dichloroethane (CH<sub>3</sub>CHCl<sub>2</sub>) both chlorines sit on one carbon, the defining feature of a geminal dihalide.
SN2 proceeds in a single step with backside attack and inversion of configuration, while SN1 forms a planar carbocation intermediate first, leading to racemisation.
Concept context
Study carbon-halogen compounds: how they are made, how they react via SN1/SN2 and elimination, their stereochemistry, and their environmental impact.