How could you distinguish 2 barium chloride from solid barium sulfate?
The correct answer and explanation is:
To distinguish between solid barium chloride (BaCl2) and barium sulfate (BaSO4), one can use a simple qualitative test based on solubility differences.
1. Solubility Test:
- Barium Chloride (BaCl2): It is highly soluble in water. When barium chloride is dissolved in water, it dissociates into barium ions (Ba2+) and chloride ions (Cl−).
- Barium Sulfate (BaSO4): In contrast, barium sulfate is virtually insoluble in water. If BaSO4 is placed in water, it will remain as a solid without dissolving.
To test for solubility, you would add a small amount of water to both substances. Barium chloride will dissolve, forming a clear solution, whereas barium sulfate will not dissolve and will remain as a solid.
2. Reaction with Hydrochloric Acid (HCl):
- Barium Chloride (BaCl2): When a solution of BaCl2 is reacted with dilute hydrochloric acid, it does not show any significant changes because BaCl2 is already in its ionic form.
- Barium Sulfate (BaSO4): Adding hydrochloric acid to solid barium sulfate will not cause any noticeable reaction. Barium sulfate remains unaffected due to its insolubility in water and its resistance to reacting with acids.
Thus, the solubility test is the most straightforward way to distinguish between the two compounds.
3. Precipitation Test:
- Another way to confirm BaCl2 is by adding a sulfate solution like sodium sulfate (Na2SO4) to a BaCl2 solution. This will cause a white precipitate of barium sulfate (BaSO4) to form. This test works because BaSO4 is insoluble in water.
In conclusion, the primary distinguishing factor is that barium chloride is soluble in water, while barium sulfate is not. Additionally, barium sulfate remains unreactive with hydrochloric acid, making it easy to differentiate the two substances in a laboratory setting.