兩條關於Neutralization的簡單化學選擇題

1.
The answer is D.

All metal hydroxides have basic properties, and can neutralize (dissolve in) dilute strong acids, i.e.
Cu(OH)2(s) + 2H+(aq) → Cu2+(aq) + 2H2O(l)
Fe(OH)2(s) + 2H+(aq) → Fe2+(aq) + 2H2O(l)
2Fe(OH)3(s) + 6H+(aq) → 2Fe3+(aq) + 3H2O(l)
Zn(OH)2(s) + 2H+(aq) → Zn2+(aq) + 2H2O(l)

Among all metal hydroxides, only some of them can neutralize (dissolve in) dilute strong alkalis. These metal hydroxides are known as amphoteric hydroxides. An amphoteric hydroxide is a (metal) hydroxide which can neutralize in both a dilute strong acid and a dilute strong alkali. The three commonest amphoteric hydroxides are aluminium hydroxide, zinc hydroxide and lead(II) hydroxide, i.e.
Al(OH)3(s) + OH-(aq) → [Al(OH)4]-(aq)
Zn(OH)2(s) + 2OH-(aq) → [Zn(OH)4]2-(aq)
Pb(OH)2(s) + 2OH-(aq) → [Pb(OH)4]2-(aq)

In the question, the four given metal hydroxides, like all other metal hydroxides, can dissolve in dilute hydroxide acid. Among them, only zinc hydroxide is amphoteric, which can also dissolve in dilute sodium hydroxide solution.


2.
The answer is C.

A/D are incorrect.
The carbonates can dissolve in (react with) dilute hydrochloric acid with the evolution of carbon dioxide gas.
CaCO3(s) + 2H+(aq) → Ca2+(aq) + CO2(g) + H2O(l)
ZnCO3(s) + 2H+(aq) → Zn2+(aq) + CO2(g) + H2O(l)
The carbonates do not dissolve (do not react) with dilute sodium hydroxide solution.

B is incorrect.
Copper(II) hydroxide dissolves in (neutralizes) dilute hydrochloric acid without the evolution of any gas.
Cu(OH)2(s) + 2H+(aq) → Cu2+(aq) + 2H2O(l)
Copper(II) hydroxide does not dissolve (does not react) with dilute sodium hydroxide solution.

C is correct.
Lead(II) hydroxide is an amphoteric acid, and it can dissolve in (neutralize) both dilute hydrochloric acid and dilute sodium hydroxide solution without the evolution of any gas.
Pb(OH)2(s) + 2H+(aq) → Pb2+(aq) + 2H2O(l)
Pb(OH)2(s) + 2OH-(aq) → [Pb(OH)4]2-(aq)
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