How do you differentiate inorganic salts by precipitation with different anions?

Question

Caleb Adams · Accepted Answer

Unfortunately, solubility is pretty random, and it's hard to give you a pattern on the periodic table for everything. You may have to memorize most, but there are some helpful exceptions!

In group 2A, Ca, Sr, and Ba (all right next to each other) cations coupled with #S^2-# and #OH^-# anions are still soluble, although most compounds with those anions are insoluble. Furthermore any group 1A element or ammonia coupled with the characteristic, common insoluble anions (#S^2-#, #CO_3^(2-)#, #PO_4^(3-)#, #OH^-#) are also soluble! Honestly, rather than throw so much information that I memorized at you, you should search "Solubility Guidelines for Common Ionic Compounds in Water" and stare at and practice with that table for a few days to totally understand this. It's a lot!

Ellie Andrews · Answer

#"How do you differentiate.......?"#

#"How else but by experiment.............?"#

The following generalizations can be made regarding solubility rules in general. They are primarily based on solubilities in which the COUNTERION, also known as "the gegenion," is an anion.

Ammonium and all of the alkali metal salts are soluble.

Each and every nitrate and perchlorate is soluble.

All halides are soluble EXCEPT for # AgX, Hg_2X_2, PbX_2"#.

All sulfates are soluble EXCEPT for #PbSO_4, BaSO_4, HgSO_4#.

All sulfides and oxides are insoluble, as are all carbonates and hydroxides; transition metal oxides and main group metal oxides typically have solubility comparable to that of bricks.

The given rules follow a hierarchy. Alkali metal and ammonium salts tend to be soluble in all circumstances. The one exception to this rule is #K^(+)""^(-)BPh_4# and #NH_4^(+)""^(-)BPh_4#, both of which are as soluble as bricks. #Na^+""^(-)BPh_4#, the which has some aqueous solubility, is sold as #"kalignost"#, i.e. #"potassium recognizer"#.............on the basis of the following reaction.....

#Na^(+)BPh_4^(-)(aq)+KX(aq) rarr K^(+)BPh_4^(-)(s)darr + NaX(aq)#

Wyatt Atkins · Answer

undefined Inorganic salts can be differentiated by precipitation reactions with specific anions. By adding different reagents containing specific ions, you can induce precipitation reactions with the ions present in the solution, forming insoluble salts. By observing the precipitates formed, you can identify the original ions present in the solution. The choice of reagent depends on the ions you want to test for. For example:

1. Carbonate ion (CO₃²⁻) can be detected by adding dilute hydrochloric acid (HCl), which produces effervescence due to the release of carbon dioxide gas.
2. Sulfate ion (SO₄²⁻) can be detected by adding barium chloride (BaCl₂), which forms a white precipitate of barium sulfate (BaSO₄).
3. Chloride ion (Cl⁻) can be detected by adding silver nitrate (AgNO₃), which forms a white precipitate of silver chloride (AgCl).
4. Bromide ion (Br⁻) can be detected similarly to chloride ion by adding silver nitrate, forming a pale yellow precipitate of silver bromide (AgBr).
5. Iodide ion (I⁻) can be detected similarly to chloride and bromide ions by adding silver nitrate, forming a yellow precipitate of silver iodide (AgI).

By carefully choosing the appropriate reagents and observing the formed precipitates, you can differentiate between various inorganic salts based on their constituent ions.