chem!!氯化鋅(zinc chloride)顏色

請問氯化鋅(zinc chloride)係咩顏色?

Zinc chloride is a white solid, and aqueous zinc chloride solution is colourless.

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同埋點樣分別zinc chloride solution and magnesium chloride solution?

Method 1:
Add separately sodium hydroxide solution dropwise to the two solutions until in excess.
Zinc chloride solution firstly gives a white precipitate, and the precipitate re-dissolves in excess sodium hydroxide solution.
Zn2+(aq) + OH-(aq) → Zn(OH)2(s)
Zn(OH)2(s) + 2OH-(aq) → [Zn(OH)4]2-(aq)
Magnesium chloride solution gives a white precipitate, but the precipitate does not re-dissolves in excess sodium hydroxide solution.
Mg2+(aq) + OH-(aq) → Mg(OH)2(s)

Method 2:
Add separately ammonia solution dropwise to the two solutions until in excess.
Zinc chloride solution firstly gives a white precipitate, and the precipitate re-dissolves in excess ammonia solution.
Zn2+(aq) + OH-(aq) → Zn(OH)2(s)
Zn(OH)2(s) + 4NH3(aq) → [Zn(NH3)4]2+ + 2OH-(aq)
Magnesium chloride solution gives a white precipitate, but the precipitate does not re-dissolves in excess ammonia solution.
Mg2+(aq) + OH-(aq) → Mg(OH)2(s)
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