Final answer:
The clear jelly-like precipitate that forms when aluminum nitrate and sodium hydroxide react is aluminum hydroxide. It dissolves upon the addition of more sodium hydroxide to form sodium aluminate. The precipitate can reappear when an acid is added, allowing for further processing to obtain aluminum oxide and eventually aluminum metal.
Step-by-step explanation:
When aluminum nitrate and sodium hydroxide are reacted, a clear jelly-like precipitate of aluminum hydroxide, Al(OH)3, is initially formed. As more sodium hydroxide is added to the solution, the precipitate dissolves and forms sodium aluminate, Na[Al(OH)4]. If even more reagent is added, excess hydroxide ions (OH-) react with the aluminate, keeping it in solution as sodium aluminate. The process involves the reprecipitation of aluminum hydroxide upon the addition of acid to the aluminate in the solution following filtration to remove impurities.
The reaction can be described by the equation: Na[Al(OH)4](aq) + H3O+ (aq) → Al(OH)3 (s) + Na+ (aq) + 2H2O(l). This precipitated aluminum hydroxide can be further processed to form aluminum oxide, Al2O3, by heating and then using electrolysis to produce aluminum metal.