Spectrophotometric determination of calcium

Prokopov, Theodore S.

doi:10.1007/bf01218174

Cited by 4 publications

(2 citation statements)

References 2 publications

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“…There are very few hazards associated with this experiment. The corrosive H 2 SO 4 used earlier (8) has been replaced by Na 2 SO 4 . Concentrated HNO 3 (6) used to oxidize Fe 2+ to Fe 3+ has been replaced by 6% H 2 O 2 , which is less corrosive.…”

Section: Hazardsmentioning

confidence: 99%

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Greener Alternative to Qualitative Analysis for Cations without H2S and Other Sulfur-Containing Compounds

Sidhwani¹,

Chowdhury²

2008

J. Chem. Educ.

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Qualitative analysis of inorganic salts and mixtures is an essential experiment carried out in high school, undergraduate, and postgraduate levels all over the world especially in India and South Asia. The classical technique uses H2S, which is highly toxic and has adverse effects on humans and the environment. Increasing awareness concerning a healthy environment has prompted us to develop a green scheme for detection of cations. NH4 + and K+ are detected directly in group zero. Pb2+ and Ag+ are detected in group I as chlorides using dilute HCl. Ca2+, Sr2+, Ba2+, and Pb2+ are precipitated in group II as sulfates using Na2SO4(aq) and ethanol. Cu2+, Cd2+, Fe3+, Mn2+, Co2+, Ni2+, and Mg2+ are precipitated as hydroxides using NaOH and H2O2 in group III. The precipitate is treated with NH3(aq) leaving a residue (group IIIA: Fe3+, Mn2+, Mg2+ as hydroxides) and the centrifugate (group IIIB: Cu2+, Cd2+, Ni2+, Co2+ as soluble ammines). Al3+, Zn2+, Sn2+/Sn4+ (as soluble hydroxo complexes), and Cr3+ (as CrO4 2-) are detected in group IV, in the presence of each other by using selective reagents. The separation is sharp; individual cations are detected by spot tests and conventional methods. This scheme is simple and fast and makes green chemistry accessible to students.

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Section: Hazardsmentioning

confidence: 99%

“…People are aware of the difficulties associated with the H 2 S scheme (5)(6)(7)(8)(9). A shift from macro to semi-micro analysis reduces consumption of H 2 S. In situ generation of H 2 S using thioacetamide, potassium trithiocarbonate (5), ammonium sulfide, and sodium sulfide (7) have been reported but all suffer from inherent disadvantages.…”

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confidence: 99%