Question

When a solution of mixture having two inorganic salts was treated with freshly prepared ferrous sulphate in acidic medium, a dark brown ferric ion was formed when treated with ferric chloride. It gave deep red colour which disappeared on boiling and a brown red ppt was formed. The mixture contains:

• A. CO\(_3^{2-}\) & NO\(_3^{-}\)
• B. SO\(_4^{2-}\) & CH\(_3\)COO\(^-\)
• C. CH\(_3\)COO\(^-\) & FeCl\(_3\)
• D. SO\(_4^{2-}\) & CH\(_3\)COO\(^-\)

Hint:

When testing for specific ions in inorganic salts, observe changes in colour and precipitate formation which can give clues about the compounds involved.

Answer 1

The Correct Option is C

- When a mixture containing the acetates reacts with ferric chloride (FeCl\(_3\)), it forms a complex and the characteristic brown red precipitate and coloration is formed, which then disappears on boiling.
- The reaction suggests the presence of CH\(_3\)COO\(^-\) and FeCl\(_3\) in the mixture, leading to the formation of blood-red and brown colours.
Thus, the correct answer is (3), CH\(_3\)COO\(^-\) & FeCl\(_3\).