Metal Hydroxide Precipitates | GCSE Chemistry Practice
Sodium hydroxide can be used to identify metal ions by forming characteristic precipitates.
Which metal ion produces a blue precipitate with sodium hydroxide?
What is Metal Hydroxide Precipitates | Practice?
"A method of identifying metal cations by the color and solubility of the hydroxide they form."
What color flame does a Sodium (Na+) ion produce?
A student sees a lilac flame during a test. Which ion is present?
Why can a flame test be unreliable if the sample is a mixture of ions?
Hydroxide Colors
Copper(II): Blue precipitate.
Iron(II): Green precipitate.
Iron(III): Brown precipitate.
Magnesium/Calcium/Aluminium: White precipitate (Aluminium redissolves in excess NaOH).
Exam Fact: If you get a white precipitate that redissolves in excess NaOH, the ion MUST be Aluminium ($Al^{3+}$).
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