Question 65 from UPSC CSE 2025 - Current Affairs (S&T)

Question

What is the common characteristic of the chemical substances generally known as CL-20, HMX, and LLM-105, which are sometimes talked about in the media?

IASCODEX · Accepted Answer

Correct Option: B. These are explosives in military weapons

Strategy: Identify the shared context by recalling the usage context and chemical names. Each of the substances—CL-20, HMX, and LLM-105—are repeatedly cited in military and defense news in reference to explosives, not fuels or refrigerants. Recognizing keywords like 'CL-20' and 'HMX', which frequently appear in defense-related news, makes it clear they are explosives. Options relating to fuels or refrigerants can thus be quickly eliminated.

Key Info: CL-20 (Hexanitrohexaazaisowurtzitane), HMX (High Melting Explosive or Octogen), and LLM-105 (2,6-diamino-3,5-dinitropyrazine-1-oxide) are all high-energy explosives developed for military applications.

- CL-20 is known for being the most powerful non-nuclear explosive; it was developed for use in advanced munitions and offers higher energy density compared to traditional explosives like RDX and HMX, but its high sensitivity to external stimuli limits operational use.
- HMX is widely used in plastic explosives, missile warheads, and as a booster in nuclear weapons; it is more powerful than RDX and notable for its high detonation velocity and pressure.
- LLM-105 is a newer, less sensitive explosive, designed to combine high energetic performance with decreased vulnerability to accidental detonation (termed 'insensitive munition'). This makes it attractive for safer storage, transport, and handling in military contexts.

None of these substances serve as refrigerants (like hydrofluorocarbons) or as primary fuels for rocket propulsion or cruise missiles, but rather as energetic materials for warheads, detonators, or munitions.

IASCODEX · Answer

Option A: These are alternatives to hydrofluorocarbon refrigerants

IASCODEX · Answer

Option C: These are high-energy fuels for cruise missiles

IASCODEX · Answer

Option D: These are fuels for rocket propulsion