Chemistry
| Action of Alkalis — on oxides and hydroxides of certain metals | |
|---|---|
| 19. Zinc oxide | ZnO + NaOH ⟶ …………… + …………… |
| 20. Zinc hydroxide | Zn(OH)2 + NaOH ⟶ …………… + …………… |
| 21. Lead [II] oxide | PbO + NaOH ⟶ …………… + …………… |
| 22. Lead hydroxide | Pb(OH)2 + NaOH ⟶ …………… + …………… |
| 23. Aluminium oxide | Al2O3 + NaOH ⟶ …………… + …………… |
| 24. Aluminium hydroxide | Al(OH)3 + KOH ⟶ …………… + …………… |
Answer
| Action of Alkalis — on oxides and hydroxides of certain metals | |
|---|---|
| 19. Zinc oxide | ZnO + 2NaOH ⟶ Na2ZnO2 + H2O |
| 20. Zinc hydroxide | Zn(OH)2 + 2NaOH ⟶ Na2ZnO2 + 2H2O |
| 21. Lead [II] oxide | PbO + 2NaOH ⟶ Na2PbO2 + H2O |
| 22. Lead hydroxide | Pb(OH)2 + 2NaOH ⟶ Na2PbO2 + 2H2O |
| 23. Aluminium oxide | Al2O3 + 2NaOH ⟶ 2NaAlO2 + H2O |
| 24. Aluminium hydroxide | Al(OH)3 + KOH ⟶ KAlO2 + 2H2O |
Related Questions
Action of Ammonium Hydroxide — on solutions of salts 7. Magnesium chloride MgCl2 + NH4OH ⟶ …………… + …………… ↓ 8. Iron [II] sulphate FeSO4 + NH4OH ⟶ …………… + …………… ↓ 9. Iron [III] chloride FeCl3 + NH4OH ⟶ …………… + …………… ↓ 10. Copper [II] sulphate CuSO4 + NH4OH ⟶ …………… + …………… ↓
[Cu(OH)2 + (NH4)2SO4 + NH4OH [in excess] ⟶ …………… + …………… ]11. Zinc sulphate ZnSO4 + NH4OH ⟶ …………… + …………… ↓
[Zn(OH)2 +(NH4)2SO4 + NH4OH [in excess] ⟶ …………… + ……………]12. Lead nitrate Pb(NO3)2 + NH4OH ⟶ …………… + …………… ↓ Action of Alkalis — on certain metals 13. Zinc Zn + NaOH ⟶ …………… + …………… 14. Zinc Zn + KOH ⟶ …………… + …………… 15. Lead Pb + NaOH ⟶ …………… + …………… 16. Lead Pb + KOH ⟶ …………… + …………… 17. Aluminium Al + NaOH + H2O ⟶ …………… + …………… 18. Aluminium Al + KOH + H2O ⟶ …………… + …………… Sodium hydroxide solution is added first in a small amount, then in excess to the aqueous salt solutions of:
- copper [II] sulphate
- zinc nitrate
- lead nitrate
- iron [III] sulphate
State in each case :
(i) the colour of the precipitate when NaOH is added in a small quantity;
(ii) the nature of the precipitate [i.e. soluble or insoluble] when NaOH is added in excess.
Write balanced equations for — (a) Aluminium (b) Zinc — is warmed with NaOH [caustic soda] soln.