OPSC OAS 2024 PrelimsScience & TechnologyQuestion 4
Solved previous year question from the OPSC OAS/OCS 2024 Preliminary Examination (General Studies), with the official answer key and a detailed explanation.
Question
Mustard Gas is:
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Answer & Explanation
Correct answer: (C) 2,2′-dichlorodiethylsulfide
Mustard Gas is the common name for 2,2′-dichlorodiethylsulfide, also known as sulfur mustard or bis(2-chloroethyl) sulfide.
Chemical formula: (ClCH₂CH₂)₂S
Key characteristics
- Chemical warfare agent (vesicant/blister agent)
- Used extensively during World War I
- Causes severe blistering of skin and mucous membranes
- Can cause respiratory damage when inhaled
- Has a characteristic mustard-like odor (hence the name)
- Banned under the Chemical Weapons Convention (1993)
- Cytotoxic and mutagenic effects
The compound gets its name from its pungent smell resembling mustard, though it’s actually a sulfur-containing organic compound.

