An unknown solution was treated with BaCl2 and a white precipitate formed which did not dissolve in hydrochloric acid. What anion(s) could be present in the unknown solution?
See the solubility rules.
What is the mass in grams of 16.46 mL of acetone?
To identify the possible anions present in the unknown solution, we need to analyze the reactions that occurred when BaCl2 was added. The formation of a white precipitate that did not dissolve in hydrochloric acid suggests that one of the anions present in the solution forms an insoluble compound with barium (Ba2+) ions.
The first step is to write out the reaction that occurs when BaCl2 is mixed with water:
BaCl2 (aq) + H2O (l) → Ba2+ (aq) + 2Cl- (aq)
This reaction dissociates the BaCl2 into barium ions (Ba2+) and chloride ions (Cl-). The barium ions react with the anion present in the solution to form an insoluble compound.
To identify the anion, we need to compare the solubility rules for common barium compounds. According to these rules, barium salts of sulfate (SO42-), carbonate (CO32-), and phosphate (PO43-) are insoluble in water. Therefore, these anions are potential candidates for the unknown anion in the solution.
To confirm which anion is present, we can perform additional tests. For example, if we add a small amount of sulfuric acid (H2SO4) to the precipitate and observe effervescence (bubbling), it suggests the presence of carbonate ions (CO32-). This is because the reaction between carbonate ions and sulfuric acid forms carbon dioxide gas (CO2), which leads to the effervescence.
Similarly, if we add ammonium hydroxide (NH4OH) to the precipitate and it dissolves, it indicates the presence of phosphate ions (PO43-). Barium phosphate is insoluble but can dissolve in ammonium hydroxide forming a complex.
By performing these additional tests and closely observing the reactions, we can narrow down the possible anions present in the unknown solution and determine which one is responsible for the formation of the white precipitate.