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{{Short description|Reducing agent}} |
{{Short description|Reducing agent}} |
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A '''Jones reductor''' is a |
A '''Jones reductor''' is a device used to [[redox|reduce]] [[Aqueous solution|aqueous solutions]] of metal ions. The active component is a [[zinc]] [[Amalgam (chemistry)|amalgam]].<ref name=Vogel>{{cite book |last=Mendham| first=J|author2=Denney, R.C |author3=Barnes, J.D. |author4= Thomas, M. |title=Vogel's Textbook of Quantitative Chemical Analysis|publisher=Pearson Education Ltd.|year=2000|edition=6th|pages=446–448|isbn=0-582-22628-7}}</ref> Jones reductors have been used for preparing solutions of [[Titanium(III) chloride|titanium]](III), [[vanadium]](II), [[chromium]](II), [[molybdenum]](III), [[niobium]](III), [[europium]](II), and [[uranium]](III). |
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==Preparation and use== |
==Preparation and use== |
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Amalgamated zinc is |
Amalgamated zinc is prepared by treating zinc metal with a 2% solution of [[mercury(II) chloride]]. The metal may be in the granulated form or as shavings, wool, or powder. The amalgam forms on the surface of the zinc. After washing to remove salts, the amalgam is placed in a long glass tube, similar to a [[column chromatography|chromatography column]], equipped with a stopcock.<ref name=Vogel/> The amalgam is a more effective reducing agent than zinc metal. The effluent is often air-sensitive, requiring the use of [[air-free technique]]s. |
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To use the reductor, the solution to be reduced is |
To use the reductor, the solution to be reduced is drawn through the tube. If the column is loosely packed, the solution may pass through without assistance. The length of the column or the flow rate are adjusted to effect full reduction of the soluble reagent. The effluent is also contaminated with zinc(II) salts, but they do not affect subsequent operations. These operations might include [[iodometric titration]] to determine the reducible content of the effluent. In some cases, the effluent is treated with other reagents to precipitate a compound of the reduced ions.<ref>{{cite book |author1=Ocone, L.R. |author2=Block, B.P. | |
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| ⚫ | series = [[Inorganic Syntheses]] | title = Anyhdrous Chromium(II) Acetate, Chromium(II) Acetate 1-Hydrate, and Bis(2,4-Pentanedionato)chromium(II) | volume=8 | year=1966 |pages=125–129 | doi = 10.1002/9780470132395.ch33|isbn=9780470132395 }}</ref><ref>{{cite book |doi=10.1002/9780470132333.ch19|chapter=Europium(II) Salts |year=1946 |last1=Cooley |first1=Robert A. |last2=Yost |first2=Don M. |title=Inorganic Syntheses |pages=69–73 |volume=2|isbn=9780470131619 }}</ref> |
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== Applications == |
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Amalgamated zinc is a powerful reducing agent, with a [[Standard electrode potential (data page)|standard redox potential]] of −0.76 V. The amalgam does not have a passive layer so it is a more effective reducing agent than zinc metal. The Jones reductor is useful for preparing solutions of [[Titanium(III) chloride|titanium]](III), [[vanadium]](II), [[chromium]](II), [[molybdenum]](III), [[niobium]](III) and [[uranium]](III).<ref name=Vogel/> All these ions are extremely susceptible to [[oxidation]]. For example, the reductor can be used in the preparation of crystalline [[chromous acetate]].<ref>{{cite journal |author1=Ocone, L.R. |author2=Block, B.P. | |
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==See also== |
==See also== |
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Latest revision as of 13:55, 25 November 2023
A Jones reductor is a device used to reduce aqueous solutions of metal ions. The active component is a zinc amalgam.[1] Jones reductors have been used for preparing solutions of titanium(III), vanadium(II), chromium(II), molybdenum(III), niobium(III), europium(II), and uranium(III).
Preparation and use
[edit]Amalgamated zinc is prepared by treating zinc metal with a 2% solution of mercury(II) chloride. The metal may be in the granulated form or as shavings, wool, or powder. The amalgam forms on the surface of the zinc. After washing to remove salts, the amalgam is placed in a long glass tube, similar to a chromatography column, equipped with a stopcock.[1] The amalgam is a more effective reducing agent than zinc metal. The effluent is often air-sensitive, requiring the use of air-free techniques.
To use the reductor, the solution to be reduced is drawn through the tube. If the column is loosely packed, the solution may pass through without assistance. The length of the column or the flow rate are adjusted to effect full reduction of the soluble reagent. The effluent is also contaminated with zinc(II) salts, but they do not affect subsequent operations. These operations might include iodometric titration to determine the reducible content of the effluent. In some cases, the effluent is treated with other reagents to precipitate a compound of the reduced ions.[2][3]
See also
[edit]References
[edit]- ^ a b Mendham, J; Denney, R.C; Barnes, J.D.; Thomas, M. (2000). Vogel's Textbook of Quantitative Chemical Analysis (6th ed.). Pearson Education Ltd. pp. 446–448. ISBN 0-582-22628-7.
- ^ Ocone, L.R.; Block, B.P. (1966). Anyhdrous Chromium(II) Acetate, Chromium(II) Acetate 1-Hydrate, and Bis(2,4-Pentanedionato)chromium(II). Inorganic Syntheses. Vol. 8. pp. 125–129. doi:10.1002/9780470132395.ch33. ISBN 9780470132395.
- ^ Cooley, Robert A.; Yost, Don M. (1946). "Europium(II) Salts". Inorganic Syntheses. Vol. 2. pp. 69–73. doi:10.1002/9780470132333.ch19. ISBN 9780470131619.