Chem MC acid and alkalis

2008-11-05 8:13 am

Which of the following hydroxides can react with both acid and alkali to give a salt and water?

copper (II) hydroxide
zinc hydroxide
iron (II) hydroxide
calcium hydroxide

Pls explain why this is the case! Thanks so much for the help!!

回答 (2)

Uncle Michael

2008-11-05 5:43 pm

✔ 最佳答案

The answer is zinc hydroxide.

All metal hydroxides can dissolve in (neutralize) dilute strong acid to form salts and water. However, there are a few metal hydroxides which can also dissolve in (neutralize) dilute strong alkali to form salts and water. The metal hydroxides which can dissolves in both dilute strong acid and dilute strong alkali to form salts and water are known as amphoteric hydroxides. The common amphoteric hydroxides includes aluminium hydroxide, zinc hydroxide and lead(II) hydroxide.

The equation for the reaction of zinc hydroxide with dilute strong acid:
Zn(OH)2(s) + 2H+(aq) → Zn2+(aq) + 2H2O(l)

The equation for the reaction of zinc hydroxide with dilute strong alkali:
Zn(OH)2(s) + 2OH-(aq) → [ZnO2]2-(aq) + 2H2O(l)
or: Zn(OH)2(s) + 2OH-(aq) → [Zn(OH)4]2-(aq)
=

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bcb

2008-11-14 7:50 am

zinc hydroxide

It react with acid as neutralization.
It react with alkali to form complex salt, zincate.

參考: as far as i remeber.

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