Why the solution of aluminium sulphate in water is not clear
The solution of aluminum sulfate in water is often not clear because of the formation of aluminum hydroxide precipitate. When aluminum sulfate dissolves in water, it dissociates into aluminum ions (Al3+) and sulfate ions (SO4^2-).
In an aqueous solution, aluminum ions can react with hydroxide ions (OH-) present in water to form aluminum hydroxide (Al(OH)3) precipitate. This reaction can occur because aluminum hydroxide has low solubility in water.
The formation of the aluminum hydroxide precipitate causes the solution to become cloudy or milky, giving it a non-clear appearance. The precipitate particles scatter light, resulting in reduced transparency.
To get a clearer solution of aluminum sulfate, one can try a few methods:
1. Increase the temperature: By heating the solution, it may increase the solubility of aluminum hydroxide, allowing it to remain in solution rather than forming a precipitate. However, cooling the solution again may cause the precipitate to reappear.
2. Adjust the pH: Aluminum hydroxide tends to precipitate at higher pH levels. By adding a weak acid, such as sulfuric acid (H2SO4), to decrease the pH of the solution, the formation of the precipitate can be minimized.
3. Filtration: If the goal is to obtain a clear solution, the aluminum hydroxide precipitate can be removed from the solution using filtration. A filter paper or other appropriate filter can separate the suspended solid particles from the liquid, resulting in a clear solution.
It is important to note that the formation of aluminum hydroxide precipitate is a natural occurrence and does not pose any significant health risks.