I've found two answers. One says its the determination of concentration of unknown alkali solution with the help of standard acid solution. The other says it as the determination of concentration of unknown acid solution with the help of standard alkali solution.
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3 Answers
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IUPAC's current terminology for the kinds of titrations is based on the following classification [1, p. 580]:
- nature of end-point detection (coulometric, potentiometric, amperometric, conductometric, thermoanalytical, optical, radiochemical titrations);
- nature of the reaction between analyte and reagent (acid-base, precipitation, complexometric, redox titrations);
- nature of the titrant (acidimetric, alkalimetric, iodometric, coulometric titrations).
So, alkalimetry is the term used to reflect the nature of the titrant, and the historical IUPAC's definition [2] is still correct, and shall be viewed as a type of acid-base titrimetric analysis:
2. Alkalimetry. Determination of a substance by titration with a base.
[…]
27.03. ALKALIMETRIC. An acid-base titration in which an acid is titrated with a standard solution of an alkali.
As for your confusion, it may be explained by the following footnote [2, p. 429]:
The term acidimetry has opposite meanings in different countries. For instance, in Britain and the U.S.A. it is used in both senses, i.e. determination of acid and determination with acid. In France acidimetry generally means measurement of acid, and this appears to be the original meaning of the term. However, all other usages of similar terms imply titration with, e.g. argentimetry; accordingly, to maintain consistency it is recommended that acidimetry means titration with. The same remarks apply to alkalimetry.
References
- Camões, M. F.; Christian, G. D.; Hibbert, D. B. Mass and Volume in Analytical Chemistry (IUPAC Technical Report). Pure Appl. Chem. 2018, 90 (3), 563–603. DOI: 10.1515/pac-2017-0410. (Free Access)
- Sandell, E. B.; West, T. S. Recommended nomenclature for titrimetric analysis. Pure Appl. Chem. 1969, 18 (3), 427–436. DOI: 10.1351/pac196918030427. (Free Access)
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1$\begingroup$ To quote the theatre play written by the Czech fictitious author Jára Cimrman, "Thank you, my chieftain, for supporting my case!". :-) $\endgroup$– PoutnikMay 15 at 15:15
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Practically, the right meaning is the meaning used and/or assumed in given context, circumstances, community. Use, what is more usual in your region, or perhaps better, replace it by more universal and less controversial/confusing acid-base volumetry.
I assume that the meaning of alkalimetry/acidimetry has the similar fate as the work sign convention schisma in the 1st law of thermodynamics for thermodynamic systems (work done on a system $\Delta U = Q + W$ versus work done by a system $\Delta U = Q - W$ ).
Some communities in some periods used terms acidi/alkalimetry for volumetric acid-base titration of acids/bases, as AChem suggests in his etymology analysis as measuring of acids/bases.
Some other communities in some periods used terms acidi/alkalimetry for titrations by acids/bases, like manganometry by permangate, complexo/chelatometry by EDTA etc. Manganometry or chelatonetry are not obviously volumetric analysis of manganese or EDTA contents.
Both notions have some logic in them, similarly as the mentioned opposite work sign conventions. So the right answer may be context dependent and it is always good -- as for TD work -- to explicitly write what you mean by the terms.
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$\begingroup$ If you look at the dates in the OED, the meaning has not changed since 1817. I agree that some people took the opposite meaning but that is not what a classically trained analytical chemist would understand. There are books with the title "Alkalimetry" and all they mean is measurement of base contents by standard acids. $\endgroup$– AChemMay 14 at 23:33
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$\begingroup$ @AChem It may depend on regions where classical analytical chemists were trained. I cannot speak for EN speaking countries. I did near all my titrations before I have learnt English. $\endgroup$– PoutnikMay 15 at 4:41
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$\begingroup$ But German authors also used the same def as given the EN language dictionary. I thought Czech and German sciences went hand in hand (or heavily influenced each other). $\endgroup$– AChemMay 15 at 4:46
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$\begingroup$ @AChem But CS/CZ science had strong hand in used terminology. Even you must admit inconsistency that acidbase titrations are OF and other ones BY. Some chemists may have noticed and started to use BY sense. In practical life, the term was not used much and chemists might not be sure which was correct. $\endgroup$– PoutnikMay 15 at 4:53
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$\begingroup$ This is why all these terms are no longer used in modern analytical chemistry...I saw this term after a long time. $\endgroup$– AChemMay 15 at 4:56
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It is an obsolete term but nevertheless an analytical chemist should be familiar with it. Break the word into two: alkali + -metry. Measurement of an alkali (content). In other words, you use a standardized acid during titration, and the base concentration is unknown. The opposite is acidimetry.
Please note Wikipedia definitions of acidimetry and alkalimetry are incorrect. If you look at original books from 1890s or early 1900s even from respectable German authors, they define alkalimetry as defined in the answer. I pasted the screenshot of the unabridged version of the Oxford Eng. Dict. because it is not available to public. Maybe someone started the inconsistent definitions in some handbook and some people followed the same without giving a second thought.
https://en.wikipedia.org/wiki/Acid%E2%80%93base_titration
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3$\begingroup$ Why obsolete? What is used instead of it? I think you got it confused, it takes the name after the standard solution, similar as bromatometry, manganometry or chelatonetry, not after what is determined $\endgroup$– PoutnikMay 14 at 13:55
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$\begingroup$ Acidimetry is the specialized analytic use of acid-base titration to determine the concentration of a basic (synonymous to alkaline) substances using standard acid. Alkalimetry, is the same concept of specialized analytic acid-base titration, but for an acidic substance using standard base. $\endgroup$– PoutnikMay 14 at 14:00
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$\begingroup$ @Poutnik, Since when Wikipedia became your reference for consulting good quality science? This is just the opposite what classical analytical chemists would say. I will add more details. $\endgroup$– AChemMay 14 at 14:07
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$\begingroup$ It is not reference for knowledge, it is source of handy quotes, not to type it myself. // The funny thing is I am finding both ways by searching. // In case the way you have provided is right, volumetry methods have naming inconsistency. $\endgroup$– PoutnikMay 14 at 15:04
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$\begingroup$ My CZ book Small Encyclopedia of chemistry from 1976 says(translated) alkalimetry is volumetric method to determine content of acidic substances by titration with solution of hydroxide, usually NaOH and then enumerates acidic primary standards. // Unless EN and CZ chemists used the opposite meanings for alkalimetry and acidimetry. $\endgroup$– PoutnikMay 14 at 15:35