The above website lists the solubility rules, but they should also be found in your text. The first thing that we want to do when looking at one of these problems is to first predict the products.
a. Here we are combining barium hydroxide (Ba(OH)2 ) and ammonium phosphate ( (NH4)3PO4). Reactions like this are always double displacement reactions meaning that the anions are switched to go with the opposite cation.
Ba(OH)2 + (NH4)3PO4 <=====> Ba3(PO4)2 + NH4OH
Now we need to see if the products are soluble. According to rule 1 (from the website above), all salts with NH4+ in them are soluble. However, by rule 10, phosphates are usually insoluble. So the reaction given would produce a precipitate in the form of Ba3(PO4)2
b. The rest ill follow a similar procedure.
AgNO3 + KCH3CO2 <=====> AgCH3CO2 + KNO3
By rule 4, AgCH3CO2 should be insoluble and form a precipitate since most silver salts are insoluble. KNO3 would be soluble by both rules 1 and 2.
Cu2SO4 + NaCl <=====> CuCl + Na2SO4
By rule 3, CuCl is soluble. By rules 1 and 5, Na2SO4 is also soluble. This means this reaction would not produce a precipitate.
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