Question

Как получить нерастворимые гидроксиды ????????? Примеры, пояснения

Answer 1

Растворить в водном растворе щелочи.
Al2O3 + 2NaOH + 3H2O -> 2Na[Al(OH)4]
Это правда не совсем гидрогсид алюминия, а его комплекс с щелочью.
Если нужен-таки гидроксид, то
сначала растворим оксид в кислоте, например, HCl
Al2O3 + 6HCl -> AlCl3 + 3H2O
потом добавляем понемногу щелочь. Гидроксид будет выпадать в осадок.

AlCl3 + 3NaOH -> 3NaCl + Al(OH)3
Al(OH)3 + NaOH -> Na[Al(OH)4]

Answer 2

How to Obtain Insoluble Hydroxides

To obtain insoluble hydroxides, you can use various methods depending on the specific hydroxide you are trying to obtain. Here are some examples and explanations:

1. Precipitation Reactions: Insoluble hydroxides can be obtained through precipitation reactions by mixing two solutions that contain the appropriate ions. When the ions combine, they form an insoluble hydroxide precipitate. For example: - Barium Hydroxide (Ba(OH)2): BaO + SO3 → BaSO4 - Magnesium Hydroxide (Mg(OH)2): Mg(OH)2 + 2HNO3 → Mg(NO3)2 + 2H2O - Sodium Aluminate (NaAlO2): Na2O + Al2O3 → NaAlO2 2. Neutralization Reactions: Insoluble hydroxides can also be obtained through neutralization reactions, where an acid reacts with a base to form a salt and water. Some hydroxides formed in this way may be insoluble. For example: - Sodium Hydroxide (NaOH): Na2O + H2O → 2NaOH 3. Other Methods: There are other methods to obtain insoluble hydroxides, such as thermal decomposition or redox reactions. However, the specific details depend on the hydroxide in question and the desired outcome.

It's important to note that the solubility of hydroxides can vary depending on factors such as temperature and pH. Some hydroxides may be slightly soluble under certain conditions but become more insoluble as the conditions change.

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