Question

помогите....1) К раствору годроксида натрия добавили порошок алюминия.2) Через раствор полученного вещества пропустили избыток углекислого газа. 3) Выпавший осадок отделили и прокалили. 4) Полученный продукт сплавили с карбонатом натрия.

Answer 1

1)2Al + 2NaOH + 2Н2О → 3H2↑ + 2NaAlO2

2)NaAlO2+CO2+2H2O = Al(OH)3+NaHCO3

3)2Al(OH)3=Al2O3+3H2O

4)Na2CO3 + Al2O3 = 2NaAlO2 + CO2

Answer 2

Reaction of Sodium Hydroxide with Aluminum Powder

When sodium hydroxide (NaOH) is added to aluminum powder, a reaction occurs. Here is a step-by-step explanation of the reaction:

1. Addition of Sodium Hydroxide to Aluminum Powder: Sodium hydroxide is a strong base, and aluminum is a reactive metal. When sodium hydroxide is added to aluminum powder, a reaction takes place. The reaction can be represented by the following equation:

2Al + 2NaOH + 6H2O → 2Na[Al(OH)4] + 3H2

This reaction produces sodium tetrahydroxoaluminate (Na[Al(OH)4]) and hydrogen gas (H2).

2. Passing Excess Carbon Dioxide through the Solution: After the reaction between sodium hydroxide and aluminum powder, the resulting solution is treated with excess carbon dioxide gas (CO2). This step is carried out to precipitate a specific compound from the solution. The reaction can be represented by the following equation:

Na[Al(OH)4] + CO2 → Al(OH)3 + NaHCO3

This reaction forms aluminum hydroxide (Al(OH)3) and sodium bicarbonate (NaHCO3).

3. Separation and Calcination of the Precipitate: The precipitate formed in the previous step, aluminum hydroxide (Al(OH)3), is separated from the solution. The separation can be done through filtration or other appropriate methods. The separated precipitate is then subjected to calcination, which involves heating the compound to a high temperature. Calcination converts aluminum hydroxide into aluminum oxide (Al2O3) by driving off the water molecules:

2Al(OH)3 → Al2O3 + 3H2O

This reaction results in the formation of aluminum oxide and water vapor.

4. Formation of Aluminum Sodium Carbonate: The obtained aluminum oxide (Al2O3) is then mixed with sodium carbonate (Na2CO3) and melted together. This step leads to the formation of aluminum sodium carbonate, also known as sodium aluminate (NaAlO2):

Al2O3 + Na2CO3 → 2NaAlO2 + CO2

This reaction produces sodium aluminate and carbon dioxide gas.

In summary, the reaction sequence can be described as follows: 1. Sodium hydroxide reacts with aluminum powder to form sodium tetrahydroxoaluminate and hydrogen gas. 2. Excess carbon dioxide is passed through the solution to precipitate aluminum hydroxide and sodium bicarbonate. 3. The precipitate is separated and calcined to obtain aluminum oxide. 4. Aluminum oxide is then mixed with sodium carbonate to form aluminum sodium carbonate or sodium aluminate.

Please note that the specific reaction conditions and stoichiometry may vary depending on the exact experimental setup and reactant proportions.