a-

feature I CHEMICAL PROJECTS Research Ideas for Young Chemists

Compiled by JAY A. YOUNG, King's College, Wilkes-Barre, Penna. I JOHN K. TAYLOR, National Bureau of Standards, Washington, D. C.

Rapid Detection of Cations of Copper Group See CHIVDRI, It I G e m Rdur 38, 413 (1961)

This scheme for the detection of the cations in the copper group Questions:

is based upon the preferential reduction of mercury(I1) ions by What are the limiting concentrations rif ions required by this

rnetalli<- copper, L l h relative insolubility of BiPOa in acidic solu- procedure? What ions interfere with the separations and identifications

tion, and the selective reduction 1.1 ropper(I1) ions t o nietallic deBoribBd in this can a l l .if tl,r.ç interferences c o p I d i n dithionite in :~n~mnii:u-;il solution. be eliminated by modifying the pri~viiurc'.'

Non-Cyanide Detection of Cadmium in the Presence of Copper Set CHANBR.I. R., .I. ( 'hem. Eduf . . 38, 409-10 (1961).

I n this artirle six different method? fur the separation of copper Question:

and radmiun\ are dewribed. The methods are empirical; Select am- one of the six methods ;ind determine the reactions for five ,,f ,he,, ti.e ,,.hi,.h ,I,.pur are described, which occur when the priiredure in w r i e d out. (Or, for the

third method, since the equation for the majnr reaction is given, though plausible possibilities are briefly discussed. See also the confirm this or s,,ggeut mdthfr which is c < i ~ t e n t with letter to theeditor. 38, THIS Joims~1.6-W 11960. . thedata youobtain.)

A New Qualitative Reagent for Aluminum. A Specific Qualitative Reagent for Copper See JOXES. ('. T.. AOT WILU.IMS. M. B., ,J. Chem. Edvc., 38,411 (1961) and WILLIAMS, T. I<., A X D Brtirnx. F.. J.,Cheni. Eiluc., 38, 413 (19611.

In Hie first article, the authors report that arsenazo reagent (available coiniitcn-idly; is superior to Aluininon as a specific test for :tluinintini. A reddish-purple color results when :t solution of ursm:ti',) ~ ~ i i ; c n t is iiddpd to :I solution containing alurninum ions.

In the second virtido, the prwipitution at pH's near neutrality of a green compound fornicd when u solutinn of o-(p-toluyl- sulfonaroidc1 aniline is added t o a solution contuining <*bpper(II) ions is descnlied Csdiniuin dues not mterfeie

Questions:

is performed

Wilt any other t.-onipnunds. similar In the :menam reagent, also react with aluniinum ions. or n t h ions, tn provide a dis- tinctive test for iiluminum or the other rnet~il ion?

Can any compounds simil;ir to o-~,/i-li~liivl~ulffin;iinide) aniline be used as specific reagents for r i ippr or iirlier iiiftal ions?

Why, do you think, t.lie amenam rwgcmt is superior to the commonly used Aluminon reagent for the detwtion of aluminum?

Cun you account fur the fact that n-ip-toluylsulfonamide) aniline does not react with cadmium ions. mid is, therefore, a suitable reagent for distinguishing copper from f-admiurn?

Benzenoid Nitro Compounds as Organic Reagents for ~ in( l l ) See BURNS, R L . I V D GRVEV. F. M , J . Chem Educ, 38, 410-11 (1961).

Three different benzenoid nitro compounds-the dye, naphthol identify the products formed and determine the reactions which yellow-& 2,&di1dtroplienol, and ineta-dinitrohenzene~all give occur. characteristic colored compounds in the presence of the tin(11) ion. Presumably, the tinGI) ion reduces the nitro groups and Are there any other reducible organic reagents which will

then chelate with the redured prodwt to form n colored complex, serve asident'ifying reagents t iutll)ion?

though this is not certain. Are there any other inorganic ions, in addition t o tin(II),

Questions: which will reduce, or otherwise react with, nitro compounds t o produce a characteristic result, that can be used t o identify these

What is the reaction or reactions which take place when tin(1l) ions? ion reacts with any one of the'three nitro compounds mentioned?

Can you find any other nitro compounds which will also Can this test be used in the converse way, as a means of serve as qualitative organic reagents for tin(I1) ion? If so, identifyingdifferentorganicunknowns?

A564 / Journal of Chemical Education