1st Year Chemistry Experiment

[andie]

Hey!

 

I have to answer this question about and unknown solution: The unknown solution could be Ag+, Ba2+, or Fe 3+.To find which cations are in the solution you add the following solutions. No precipitate is formed when NaCl or Na2So4 is added to the solution. When NaOH is added a precipitate forms. Which cations are present of the 3 mentioned above?

 

I answered the question that the cations present are Ag+, and Fe3+ because they are more insoluble thatn Ba2+ which produces Ba(OH)2 (aq).

 

Am I right with the explanation or totally wrong?

 

PLEASE HELP!!!!!

[encipher]

I didn't quite understand your explanation.

 

But what I will say, is that AgCl is insoluble, and BaSO4 is insoluble, and that hydroxides are insoluble except Group IA, NH4+, Ba2+, Sr2+, Ca2+ and Tl+

hydroxides.

 

Now see, with this information, if your answer matches those criteria.

[andie]

Okay i understand what you are saying. So then then solution contains the Ag+, and Fe3+. Right?

[encipher]

How could silver be present, if when NaCl is added, no precipitate is formed? AgCl is insoluble, remember. therefore if a chloride salt is added to a solution containing the Ag+ ion, it will precipitate out AgCl. Therefore the only remaining answer is Fe3+, since only iron(III) hydoxide is the only insoluble Fe salt out of those three.

[andie]

excellent thank you!