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Question
What would you observe in the following cases:
Ammonium hydroxide is first added in a small quantity and then in excess to a solution of copper sulphate.
Solution
Adding a tiny amount of ammonium hydroxide produces blue precipitates. Excess ammonium hydroxide dissolves blue precipitates, yielding a vivid blue solution.
\[\ce{CuSO4 + 2NH4OH -> \underset{Blue ppt}{Cu(OH)2}↓ + (NH4)2SO4}\]
In excess
\[\ce{Cu(OH)2 + (NH4)2SO4 + 2NH4OH -> \underset{Deep Blue Solution}{[Cu(NH3)4]SO4} + 4H2O}\]
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RELATED QUESTIONS
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|
Chemical Test |
Observation | Conclusion |
| To Solution X, ammonium hydroxide is added in minium quantity first and then in excess | A dirty white precipitate is formed which dissolves in excess to form a clear solution | (i) |
| To Solution Y, ammonium hydroxide is added in minimum quantity first and then in excess | A pale blue precipitate is formed which dissolves in excess to form a clear inky blue solution | (ii) |
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