Вопрос
3. Amphoteric hydroxides a) Take 5-6 drops of a solution of any chromium (III) salt and add dropwise a diluted solution of sodium hydroxide until the precipitate of chromium hydroxide is formed. Divide the precipitate of Cr(OH)_(3) into two parts and dissolve them in NaOH and HCl respectively. Observation __
Решения
4.5
(134 Голоса)
Наталья
профессионал · Репетитор 6 лет
Ответ
To complete the observation for the given experiment, we need to understand the behavior of chromium(III) hydroxide (\(Cr(OH)_3\)) in different solutions.When \(Cr(OH)_3\) is dissolved in sodium hydroxide (NaOH), a strong base, the hydroxide ions (OH-) from NaOH will not significantly change the equilibrium of \(Cr(OH)_3\). Therefore, the solution will remain blue, indicating that the chromium(III) ions are in their hydroxide form and not significantly altered by the presence of excess hydroxide ions.On the other hand, when \(Cr(OH)_3\) is dissolved in hydrochloric acid (HCl), a strong acid, the hydrogen ions (H+) from HCl will react with the hydroxide ions from \(Cr(OH)_3\), forming water and leaving the chromium(III) ions in a different oxidation state. This change in oxidation state will result in a green solution.Therefore, the observation for the experiment would be:- When \(Cr(OH)_3\) is dissolved in NaOH, the solution remains blue.- When \(Cr(OH)_3\) is dissolved in HCl, the solution turns green.This confirms that \(Cr(OH)_3\) is amphoteric, as it can dissolve in both basic and acidic solutions, resulting in different colors.