Question

How would you test for the presence of the following ions in aqueous solution of an unknown salt? Kindly provide name of the test and a balanced chemical equation.

(i) I-
(ii) CO 2-3
(iii) Ag+
(iv) Ba2+

Answer 1

To test for the presence of I-, CO3^2-, Ag+, and Ba2+ ions in a solution, use silver nitrate for iodide, hydrochloric acid for carbonate, sodium chloride for silver and sodium sulfate for barium ions, respectively.

Step-by-step explanation:

To test for the presence of specific ions in an aqueous solution of an unknown salt, you would perform precipitation reactions and look for a resulting solid, which indicates a precipitate has formed. Here are the tests for each ion you mentioned:

• I-: Add a few drops of silver nitrate (AgNO3) to the solution. A yellow precipitate of silver iodide (AgI) confirms the presence of iodide ions. The balanced chemical equation is: AgNO3(aq) + KI(aq) → KNO3(aq) + AgI(s).
• CO32-: Add a drop of hydrochloric acid (HCl) to the solution and look for the formation of bubbles or fizzing, which indicates the release of carbon dioxide gas. The balanced chemical equation is: 2 HCl(aq) + Na2CO3(aq) → 2 NaCl(aq) + H2O(l) + CO2(g).
• Ag+: Add a few drops of sodium chloride (NaCl) to the solution. A white precipitate of silver chloride (AgCl) confirms the presence of silver ions. The balanced chemical equation is: AgNO3(aq) + NaCl(aq) → NaNO3(aq) + AgCl(s).