How could tell a copper (II)sulfate solution from lead (II)nitrate or sodium sulfite if the solutions were not labeled ?
CuSO4 is blue; the others are colorless (note I didn't say clear).
To distinguish between a copper (II) sulfate solution, lead (II) nitrate, and sodium sulfite solution without labels, you can perform a series of simple chemical tests. Here's how you can do it:
1. Test for sulfates:
- Add a few drops of dilute hydrochloric acid (HCl) to a small portion of each solution.
- Then, add a few drops of barium chloride (BaCl2) solution to the acidified solutions.
- If a white precipitate forms, it indicates the presence of sulfates. In this case, it would confirm the copper (II) sulfate solution since it contains sulfate ions (SO4 2-). Lead (II) nitrate and sodium sulfite do not contain sulfates.
2. Test for copper (II) ions:
- Take a small portion of each solution and add a few drops of ammonium hydroxide (NH4OH) to it.
- If a blue precipitate forms, it indicates the presence of copper (II) ions, confirming the copper (II) sulfate solution. Lead (II) nitrate and sodium sulfite do not produce a blue precipitate.
3. Test for lead (II) ions:
- Take a small portion of each solution and add a few drops of potassium iodide (KI) solution.
- If a yellow precipitate forms, it indicates the presence of lead (II) ions, indicating the solution to be lead (II) nitrate. Copper (II) sulfate and sodium sulfite do not produce a yellow precipitate.
4. Test for sulfite ions:
- Take a small portion of each solution and add a few drops of hydrochloric acid (HCl).
- Then, add a few drops of hydrogen peroxide (H2O2) solution.
- If you observe a vigorous gas evolution, it indicates the presence of sulfite ions, confirming the solution to be sodium sulfite. Copper (II) sulfate and lead (II) nitrate would not produce such a strong gas evolution.
By performing these chemical tests, you can identify the copper (II) sulfate, lead (II) nitrate, and sodium sulfite solutions, even without labels. However, it's important to exercise caution and use appropriate lab safety protocols while conducting these tests.