hydrogen chloride
Low (Specialist)Technical / Scientific
Definition
Meaning
A colourless, pungent gas with the chemical formula HCl.
When dissolved in water, it forms hydrochloric acid, a strong mineral acid used in industry and laboratory settings.
Linguistics
Semantic Notes
The term specifically denotes the pure gaseous compound HCl; the aqueous solution is 'hydrochloric acid'. In industrial contexts, it may be referred to simply as 'HCl'.
Dialectal Variation
British vs American Usage
Differences
No significant lexical differences. Spelling conventions for related terms follow regional norms (e.g., colourless/colorless).
Connotations
Neutral and purely technical in both regions.
Frequency
Equally low-frequency outside of chemical, industrial, or educational contexts.
Vocabulary
Collocations
Grammar
Valency Patterns
Hydrogen chloride is produced BY [process].Hydrogen chloride reacts WITH [compound].[Substance] dissolves IN hydrogen chloride.Vocabulary
Synonyms
Neutral
Usage
Context Usage
Business
Discussed in contracts for chemical supply or industrial safety reports.
Academic
Common in chemistry textbooks and research papers on inorganic synthesis or atmospheric chemistry.
Everyday
Virtually never used; 'hydrochloric acid' is more common for general reference to the corrosive solution.
Technical
Precise term in chemical engineering, process descriptions, and material safety data sheets (MSDS).
Examples
By CEFR Level
- Hydrogen chloride is a gas with a sharp smell.
- Workers must be careful with hydrogen chloride in the factory.
- The direct combination of hydrogen and chlorine yields hydrogen chloride.
- When hydrogen chloride dissolves, it ionises completely.
- Anhydrous hydrogen chloride is often used as a catalyst in Friedel-Crafts alkylation reactions.
- The emission of hydrogen chloride from waste incineration is a significant environmental concern.
Learning
Memory Aids
Mnemonic
Think of it as the 'hydrogen' part of 'hydrochloric acid' before it meets water.
Conceptual Metaphor
Often conceptualised as a BUILDING BLOCK or PRECURSOR to a more commonly known substance (the acid).
Watch out
Common Pitfalls
Translation Traps (for Russian speakers)
- Do not confuse with 'соляная кислота' (hydrochloric acid). 'Хлороводород' is the direct translation for the gas.
Common Mistakes
- Using 'hydrogen chloride' to refer to the liquid acid.
- Omitting the space: 'hydrogen chloride' is correct, not 'hydrogenchloride'.
- Mispronouncing 'chloride' as /ˈklɒr.ɪd/ instead of /ˈklɔː.raɪd/.
Practice
Quiz
What is the primary industrial use of hydrogen chloride gas?
FAQ
Frequently Asked Questions
No. Hydrogen chloride (HCl) is the pure gaseous compound. Hydrochloric acid is the aqueous solution of HCl in water.
It is highly corrosive, toxic, and forms hydrochloric acid upon contact with moisture in the eyes, skin, or respiratory tract.
It is most commonly produced as a by-product of the chlorination of organic compounds or by reacting salt with sulfuric acid.
Yes, in minute quantities in volcanic gases. It is also a trace component of the atmosphere.