Question

Find the odd one with reasons [valency is not a criterion] :
1. Al(OH)3
2. Pb(OH)2
3. Mg(OH)2
4. Zn(OH)2

July 31, 2024

Answer

Mg(OH)₂

Reason

All others are amphoteric hydroxides.

💡 Some Related Questions

Action of Alkalis — on oxides and hydroxides of certain metals
Zinc oxide ZnO + NaOH ⟶ +
Zinc hydroxide Zn(OH)₂ + NaOH ⟶ +
Lead [II] oxide PbO + NaOH ⟶ +
Lead hydroxide Pb(OH)₂ + NaOH ⟶ +
Aluminium oxide Al₂O₃ + NaOH ⟶ +
Aluminium hydroxide Al(OH)₃ + KOH ⟶ +

Action of Alkalis — on certain metals
Zinc Zn + NaOH ⟶ +
Zinc Zn + KOH ⟶ +
Lead Pb + NaOH ⟶ +
Lead Pb + KOH ⟶ +
Aluminium Al + NaOH + H₂O ⟶ +
Aluminium Al + KOH + H₂O ⟶ +

Action of Ammonium Hydroxide – on solutions of salts
Magnesium chloride MgCl₂ + NH₄OH ⟶ + ↓
Iron [II] sulphate FeSO₄ + NH₄OH ⟶ + ↓
Iron [III] chloride FeCl₃ + NH₄OH ⟶ + ↓
Copper [II] sulphate CuSO₄ + NH₄OH ⟶ + ↓ [Cu(OH)₂ + (NH₄)₂SO₄ + NH₄OH [in excess] ⟶ + ]
Zinc sulphate ZnSO₄ + NH₄OH ⟶ + ↓ [Zn(OH)₂ +(NH₄)₂SO₄ + NH₄OH [in excess] ⟶ + ]
Lead nitrate Pb(NO₃)₂ + NH₄OH ⟶ + ↓

Complete and balance the equations
Pb(NO3)2 + NaOH ⟶ …………… + …………… ↓
[Pb(OH)2 + NaOH [in excess] ⟶ …………… + ……………]

Complete and balance the equations
ZnSO4 + NaOH ⟶ …………… + …………… ↓
[Zn(OH)2 + NaOH [in excess] ⟶ …………… + ……………]

Complete and balance the equations
CuSO4 + NaOH ⟶ …………… + …………… ↓

Complete and balance the equations
FeCl3 + NaOH ⟶ + ↓

Complete and balance the equations
MgCl2 + NaOH ⟶ + ↓

Complete and balance the equations
Ca(NO3)2 + NaOH ⟶ + ↓

Oxides and hydroxides of certain metals i.e [iron/ zinc / copper / aluminium / magnesium / lead] are amphoteric and react with [acids / alkalis / acids and alkalis] to give salt and water.