Question #8a5f1

1 Answer
Jun 29, 2015

Na_2ZnO_(2(aq))+2HCl_((aq))rarrZnO_((s))+H_2O_((l))+NaCl_((aq))Na2ZnO2(aq)+2HCl(aq)ZnO(s)+H2O(l)+NaCl(aq)

Explanation:

The ions present in sodium zincate are Na^(+)Na+ and zincate which is ZnO_2^(2-)ZnO22.

Zinc oxide is amphoteric, which means that it can react react with both acid and base.

Sodium zincate is formed if zinc oxide is treated with an alkali such as NaOHNaOH:

ZnO_((s))+2NaOH_((aq))rarrNa_2ZnO_(2(aq))+H_2O_((l))ZnO(s)+2NaOH(aq)Na2ZnO2(aq)+H2O(l)

We can reverse the process by adding acid:

Na_2ZnO_(2(aq))+2HCl_((aq))rarrZnO_((s))+H_2O_((l))+NaCl_((aq))Na2ZnO2(aq)+2HCl(aq)ZnO(s)+H2O(l)+NaCl(aq)

The zincate ion is written more precisely as Zn(OH)_(4(aq))^(2-)Zn(OH)24(aq).

Adding acid would remove 2 OH^-OH ions to leave a white precipitate of zinc hydroxide Zn(OH)_(2(s)Zn(OH)2(s).