hydrosulphurous acid
Extremely Low (Academic/Specialist Historical)Highly technical, historical, obsolete
Definition
Meaning
A theoretical or historical chemical name referring to an oxyacid of sulfur in a lower oxidation state, specifically thiosulfuric acid (H₂S₂O₃).
In older chemical nomenclature, it was used to denote an acid derived from sulfurous acid with additional sulfur, but the term is largely obsolete in modern chemistry, having been superseded by more precise IUPAC names.
Linguistics
Semantic Notes
This term is a historical artifact from a period of inconsistent chemical naming. It does not refer to a commonly encountered substance in modern practice. Its meaning is essentially synonymous with 'thiosulfuric acid'.
Dialectal Variation
British vs American Usage
Differences
The primary difference is in the spelling of 'sulphur' (UK) vs. 'sulfur' (US). The US variant would be 'hydrosulfurous acid'.
Connotations
In both regions, the term connotes outdated, 19th or early 20th-century chemical literature.
Frequency
The term is exceptionally rare in modern texts in both varieties. Its occurrence is almost exclusively in historical contexts or discussions of obsolete nomenclature.
Vocabulary
Collocations
Grammar
Valency Patterns
[The term] hydrosulphurous acid [is/was] used [for/to describe]...Vocabulary
Synonyms
Strong
Neutral
Weak
Vocabulary
Antonyms
Usage
Context Usage
Business
Not used.
Academic
Used only in historical analyses of chemical terminology or in footnotes of older texts.
Everyday
Never used.
Technical
Rarely, if ever, used in modern technical writing. Appears only as a point of reference for outdated nomenclature.
Examples
By Part of Speech
adjective
British English
- The hydrosulphurous acid compound was unstable.
American English
- The hydrosulfurous acid formulation is archaic.
Examples
By CEFR Level
- Hydrosulphurous acid is an obsolete chemical term.
- In his 1880 treatise, the author referred to the product as hydrosulphurous acid, a term we now recognise as thiosulfuric acid.
Learning
Memory Aids
Mnemonic
HYDRO (water/hydrogen) + SULPHUROUS (like sulphurous acid, but with extra sulphur) = an old name for a sulphur acid compound.
Conceptual Metaphor
LINGUISTIC FOSSIL: A term preserved only in the strata of old scientific texts.
Watch out
Common Pitfalls
Translation Traps (for Russian speakers)
- Avoid direct translation into Russian as it may not correspond to a standard modern term. Use "тиосерная кислота" (thiosulfuric acid) for accuracy.
Common Mistakes
- Using it as a current technical term.
- Confusing it with hyposulfurous acid (H₂S₂O₄) or other sulfur oxyacids.
- Misspelling 'sulphurous'/'sulfurous'.
Practice
Quiz
What is the modern IUPAC name for the compound historically called 'hydrosulphurous acid'?
FAQ
Frequently Asked Questions
No, it is not a common chemical. The name itself is obsolete and refers to thiosulfuric acid (H₂S₂O₃), which is an intermediate and not typically isolated.
The difference is between British English ('sulphur') and American English ('sulfur') spelling conventions.
Absolutely not. You should use the standard IUPAC name 'thiosulfuric acid' or its formula H₂S₂O₃ to ensure clarity and scientific accuracy.
This is a highly specialised, historical term. A learner is extremely unlikely to encounter it outside of very specific contexts studying the history of science. Recognising it as an obsolete variant of 'thiosulfuric acid' is sufficient.