An unknown solid is entirely soluble in water. On addition of dilute HCl, a precipitate forms. After the precipitate is filtered off, the pH is adjusted to about 1 and H2S is bubbled in; a precipitate again forms. After filtering off this precipitate, the pH is adjusted to 8 and H2S is again added; no precipitate forms. No precipitate forms upon addition of (NH4)2HPO4. The remaining solution shows a yellow color in a flame test. Based on these observations, which of the following compounds might be present, which are definitely present, and which are definitely absent: CdS, Pb(NO3)2, HgO, ZnSO4, Cd(NO3)2, and Na2SO4?

An unknown solid is entirely soluble in water. On addition of dilute HCl, a precipitate forms. After the precipitate is filtered off, the pH is adjusted to about 1 and H2S is bubbled in; a precipitate again forms. After filtering off this precipitate, the pH is adjusted to 8 and H2S is again added; no precipitate forms. No precipitate forms upon addition of (NH4)2HPO4. The remaining solution shows a yellow color in a flame test. Based on these observations, which of the following compounds might be present, which are definitely present, and which are definitely absent: CdS, Pb(NO3)2, HgO, ZnSO4, Cd(NO3)2, and Na2SO4?

Chemistry: Principles and Reactions

8th Edition

ISBN:9781305079373

Author:William L. Masterton, Cecile N. Hurley

Publisher:William L. Masterton, Cecile N. Hurley

Chapter14: Equilibria In Acid-base Solutions

Section: Chapter Questions

Problem 12QAP: A buffer is prepared by dissolving 0.062 mol of sodium fluoride in 127 mL of 0.0399 M hydrofluoric...

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A solution containing several metal ions is treated with diluteHCl; no precipitate forms. The pH is adjusted to about1, and H2S is bubbled through. Again, no precipitate forms.The pH of the solution is then adjusted to about 8. Again,H2S is bubbled through. This time a precipitate forms. Thefiltrate from this solution is treated with (NH4)2HPO4. Noprecipitate forms. Which of these metal cations are eitherpossibly present or definitely absent: Al3 +, Na +, Ag+, Mg2 +?
An unknown solid is entirely soluble in water. On additionof dilute HCl, a precipitate forms. After the precipitateis filtered off, the pH is adjusted to about 1 andH2S is bubbled in; a precipitate again forms. After filteringoff this precipitate, the pH is adjusted to 8 andH2S is again added; no precipitate forms. No precipitateforms upon addition of (NH4)2HPO4. The remainingsolution shows a yellow color in a flame test (see Figure). Based on these observations, which of the followingcompounds might be present, which are definitelypresent, and which are definitely absent: CdS,Pb(NO3)2, HgO, ZnSO4, Cd(NO3)2, and Na2SO4?
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