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Chemistry Forums for Students => Undergraduate General Chemistry Forum => Topic started by: FutureDoc on September 28, 2007, 08:26:27 PM

Title: Solubility and Precipitates
Post by: FutureDoc on September 28, 2007, 08:26:27 PM

Of the following anions, Br^-, CO₃^2-, Cl^-, I^-, NO₃^-, NO₂^-, PO₄^3-, SO₄^2-, SO₃^2-, list those ions that meet the following criteria:

(1)  Gives a precipitate with Ag⁺ ion that is insoluble in HNO₃.  Br^-, Cl^-, I^-

(2)  Is involved in an oxidation-reduction reaction as part of a confirmation reaction.  Br^-, Cl^-, I^-, NO₃^-

(3)  Gives a precipitate with Ba²⁺ ion that is soluble in HNO₃.  CO₃^2-, PO₄^3-

(4)  Evolves a gas when acid is needed.  CO₃^2-, NO₃^-, NO₂^-, SO₃^2-

(5)  Releases an odorous gas as a product.  NO₃^-, NO₂^-,SO₃^2-

(6)  Does not produce a precipitate in any classification or confirmatory reaction described in this experiment.  SO₄^2-

Any help is greatly appreciated. I'm stumped on this one. Are these answers close?

Thanks in advance,

FutureDoc

Title: Re: Solubility and Precipitates
Post by: FutureDoc on September 28, 2007, 10:01:08 PM

Can anyone help me with this? Please?

Title: Re: Solubility and Precipitates
Post by: Borek on September 29, 2007, 12:33:55 AM

Please read forum rules (http://www.chemicalforums.com/index.php?page=forumrules). For sure you at least know some of the answers.

Title: Re: Solubility and Precipitates
Post by: FutureDoc on September 29, 2007, 12:52:28 AM

I know the eight basic solubility rules (shown below), but those only help partway. What I don't know is the individual characteristics of each ion listed above in the problem.

1. Salts of ammonium (NH4+) and Group IA are always soluble.

2. a. All chlorides (Cl-) are soluble except AgCl, Hg2Cl2, and PbCl2 which are insoluble.
b. All bromides (Br-) are soluble except AgBr, Hg2Br2, HgBr2, and PbBr2 which are insoluble.
c. All iodides (I-) are soluble except AgI, Hg2I2, HgI2, and PbI2 which are insoluble.

3. Chlorates (ClO3-), nitrates (NO3-), and acetates (CH3COO-) are soluble.

4. Sulfates (SO4-2) are soluble except CaSO4, SrSO4, BaSO4, Hg2SO4, HgSO4,PbSO4, and Ag2SO4 which are insoluble.

5. Phosphates (PO4-3), and carbonates (CO3-2) are insoluble except NH4+ andGroup IA compounds.

6. All metallic oxides (O-2) are insoluble except NH4+ and Group IA compounds.

7. All metallic hydroxides (OH-) are insoluble except NH4+ and Group IA and Group IIA from calcium down.

8. All sulfides (S-2) are insoluble except NH4+ and Groups IA and IIA.

Sorry for the incorrect format earlier, but I'm really pretty clueless about this answer. I'm not asking the community to do my homework for me, I'd just like some insight on how these ions react with one another, and how I know if it releases a gas or not. How might I go about solving the problem in my first post?

Title: Re: Solubility and Precipitates
Post by: Borek on September 29, 2007, 09:41:29 AM

Start eliminating ones you are sure about.

Title: Re: Solubility and Precipitates
Post by: FutureDoc on September 29, 2007, 09:25:12 PM

I just need some help figuring it out. Maybe a link or something listing the properties of each ion?

Title: Re: Solubility and Precipitates
Post by: orangerevolt on September 30, 2007, 08:30:35 PM

Hey, I have this same assignment as a Pre-Lab. Go through and look at the given equations to help answer the questions. Most of the answers can be found by looking under II. Chemistry of Selected Anions. It really helps. Good luck.

Title: Re: Solubility and Precipitates
Post by: FutureDoc on October 01, 2007, 12:32:04 AM

Quote from: orangerevolt on September 30, 2007, 08:30:35 PM

Hey, I have this same assignment as a Pre-Lab. Go through and look at the given equations to help answer the questions. Most of the answers can be found by looking under II. Chemistry of Selected Anions. It really helps. Good luck.

I went back and re-read the background information given for each of the ions, but I'm still unsure about some of my answers. Would you mind letting me know if they're right or wrong? See above for my answers.

Thanks.

Title: Re: Solubility and Precipitates
Post by: FutureDoc on October 01, 2007, 09:51:44 PM

Anyone able to confirm these answers?

Title: Re: Solubility and Precipitates
Post by: FutureDoc on October 02, 2007, 02:10:33 PM

Quote from: FutureDoc on October 01, 2007, 09:51:44 PM

Anyone able to confirm these answers?