Science & Tech · DRDO & Defence Indigenisation
The concept being tested: High-energy explosives in military weapon systems.
What is the common characteristic of the chemical substances generally known as CL-20, HMX and LLM-105, which are sometimes talked about in media?
CL-20 (HNIW), HMX (octogen) and LLM-105 are nitro-based energetic compounds classified as high-energy explosives, not fuels or refrigerants. All three serve as explosive fillers or booster charges in warheads, missiles and other military ordnance, prized for combining very high detonation energy with greater thermal and impact insensitivity than older explosives such as RDX or TNT. This is why India's DRDO, through its High Energy Materials Research Laboratory, has developed indigenous CL-20 production, the kind of news that puts these names in the media. Because the trait common to all three is their identity as explosives used in weapon systems, and not any role as combustion fuel or rocket propellant, the option describing them as explosives in military weapons is the one that correctly captures what CL-20, HMX and LLM-105 actually are.
What UPSC was testing
UPSC is testing whether aspirants can separate high-energy explosives, which fill a warhead, from the fuels and propellants that power a missile's flight, a distinction the options deliberately blur by attaching missile-sounding language to every choice.
How often this comes up
This concept has appeared 4 times in UPSC Prelims General Studies Paper I between 2015 and 2025 — in 2022, 2023, 2024 and 2025.
The option-by-option autopsy for this question — why each of the other three is wrong, and which neighbouring concept each one was built from — is in the app.