Write the formula of the anion present (i.e. anions are charged; do not write compounds) in these unknowns as indicated by these test results.
1) An unknown solution was treated with ammonium hydroxide and then with barium chloride. A precipitate formed. The precipitate did not dissolve in dilute hydrochloric acid
2) An unknown was mixed with ammonium hydroxide and then with barium chloride. Nothing happened. A fresh portion was mixed with silver nitrate and again nothing happened. A third portion was treated with sulfuric acid, which produced a vinegar-like odor.
3) An unknown solution was treated with ammonium hydroxide and then with barium chloride. A precipitate formed. The precipitate dissolved in dilute hydrochloric acid and bubbles of an odorless gas were produced.
Please help with these questions. I don't understand
1 and 2 answered above.
3 is CO3^2-, carbonate.
To determine the formula of the anion present in the unknowns based on the given test results, we need to analyze each individual result and understand the reactions that took place.
1) In the first test result, when the unknown solution was treated with ammonium hydroxide and then with barium chloride, a precipitate formed. The fact that the precipitate did not dissolve in dilute hydrochloric acid indicates that the anion is not chloride (Cl-). Therefore, the anion present in this unknown solution cannot be determined with the given information.
2) In the second test result, when the unknown was mixed with ammonium hydroxide and then with barium chloride, and nothing happened, it suggests that the unknown does not contain anions that react with ammonium hydroxide or barium chloride. When a fresh portion was mixed with silver nitrate and again nothing happened, it indicates that the unknown does not contain anions that react with silver nitrate either. However, when the third portion was treated with sulfuric acid, and a vinegar-like odor was produced, it suggests the presence of acetate ion (CH3COO-). Therefore, the anion present in this unknown is acetate (CH3COO-).
3) In the third test result, when the unknown solution was treated with ammonium hydroxide and then with barium chloride, a precipitate formed. The fact that the precipitate dissolved in dilute hydrochloric acid and bubbles of an odorless gas were produced suggests that the anion present is carbonate (CO3^2-). The reaction with hydrochloric acid forming bubbles indicates the release of carbon dioxide gas (CO2).
So, based on the given test results:
1) The anion in the unknown cannot be determined.
2) The anion in the unknown is acetate (CH3COO-).
3) The anion in the unknown is carbonate (CO3^2-).