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A student was given a solid containing a mixture of nitrate salts. The sample co

ID: 1017015 • Letter: A

Question

A student was given a solid containing a mixture of nitrate salts. The sample completely dissolved in water, and upon addition of dilute HCl, no precipitate formed. The pH was lowered to about 1 and H2S was bubbled through the solution. No precipitate formed. The pH was adjusted to 8 and H2S was again bubbled in. This time, a precipitate formed. Which compounds might have been present in the unknown?

Which compounds might have been present?

Fe(NO3)3, Al(NO3)3, Zn(NO3)2, Bi(NO3)3, NaNO3, Cd(NO3)2, Sn(NO3)4, Ca(NO3)2

Explanation / Answer

The compound is Ca(NO3)2 . The remaining are precipitated out.