1. Group 2 Oxide Reactions with Water:
| Group 2 Oxide | Reaction with Water | Observations |
|---|---|---|
| MgO | MgO(s) + H₂O(l) → Mg(OH)₂(aq) | MgO is only slightly soluble in water, therefore a weakly alkaline solution is formed (pH 10) |
| CaO | CaO(s) + H₂O(l) → Ca(OH)₂(aq) | Vigorous reaction releases a lot of energy which causes some of the water to boil off as the CaO solid lump seems to expand and crack open (pH 11) |
| SrO | SrO(s) + H₂O(l) → Sr(OH)₂(aq) | |
| BaO | BaO(s) + H₂O(l) → Ba(OH)₂(aq) |
2. Reactions of Oxides with Water and pH:
| Oxide | Chemical Equation | pH | Comments |
|---|---|---|---|
| Na₂O | Na₂O(s) + H₂O(l) → 2NaOH(aq) | 12-14 (strongly alkaline) | - |
| MgO | MgO(s) + H₂O(l) → Mg(OH)₂(aq) | 8-10 (weakly alkaline) | - |
| Al₂O₃ | No reaction | - | Al₂O₃ is insoluble in water |
| SiO₂ | No reaction | - | SiO₂ is insoluble in water |
| P₄O₁₀ | P₄O₁₀(s) + 6H₂O(l) → 4H₃PO₄(aq) | 3-4 (weakly acidic) | Vigorous reaction |
| SO₂, SO₃ | SO₂(g) + H₂O(l) → H₂SO₃(aq) SO₃(g) + H₂O(l) → H₂SO₄(aq) |
1-2 (strongly acidic) | - |
3. Oxide Reactions:
| Oxide | Chemical Equation | Comments |
|---|---|---|
| Na₂O | Na₂O(s) + 2HCl(aq) → 2NaCl(aq) + H₂O(l) Na₂O(s) + H₂O(l) → 2NaOH(aq) |
Used in indigestion remedies by neutralizing the excess acid in the stomach |
| MgO | MgO(s) + 2HCl(aq) → MgCl₂(aq) + H₂O(l) | |
| Al₂O₃ | Al₂O₃(s) + 3H₂SO₄(aq) → Al₂(SO₄)₃(aq) + 3H₂O(l) Al₂O₃(s) + 2NaOH(aq) + 3H₂O(l) → 2NaAl(OH)₄(aq) |
Reacts with acid to form salt and water Reacts with hot, concentrated alkali to form a salt |
| SiO₂ | SiO₂(s) + 2NaOH(aq) → Na₂SiO₃(aq) + H₂O(l) | Reacts with hot, concentrated alkali to form a salt and water |
| P₄O₁₀ | P₄O₁₀(s) + 12NaOH(aq) → 4Na₃PO₄(aq) + 6H₂O(l) | |
| SO₂, SO₃ | SO₂(g) + 2NaOH(aq) → Na₂SO₃(aq) + H₂O(l) SO₃(g) + 2NaOH(aq) → Na₂SO₄(aq) + H₂O(l) |
4. Group 2 Hydroxides Reactions:
| Group 2 Hydroxide | Reaction with Dilute HCl | Reaction with Dilute H₂SO₄ |
|---|---|---|
| Mg(OH)₂ | Mg(OH)₂(s) + 2HCl(aq) → MgCl₂(aq) + 2H₂O(l) | Mg(OH)₂(s) + H₂SO₄(aq) → MgSO₄(aq) + 2H₂O(l) |
| Ca(OH)₂ | Ca(OH)₂(s) + 2HCl(aq) → CaCl₂(aq) + 2H₂O(l) | Ca(OH)₂(s) + H₂SO₄(aq) → CaSO₄(aq) + 2H₂O(l) |
| Sr(OH)₂ | Sr(OH)₂(s) + 2HCl(aq) → SrCl₂(aq) + 2H₂O(l) | Sr(OH)₂(s) + H₂SO₄(aq) → SrSO₄(aq) + 2H₂O(l) |
| Ba(OH)₂ | Ba(OH)₂(s) + 2HCl(aq) → BaCl₂(aq) + 2H₂O(l) | Ba(OH)₂(s) + H₂SO₄(aq) → BaSO₄(s) + 2H₂O(l) |
5. Carbonate Group 2 Reactions:
| Carbonate Group 2 | Reaction with Dilute HCl | Reaction with Dilute H₂SO₄ |
|---|---|---|
| MgCO₃ | MgCO₃(s) + 2HCl(aq) → MgCl₂(aq) + H₂O(l) + CO₂(g) | MgCO₃(s) + H₂SO₄(aq) → MgSO₄(aq) + H₂O(l) + CO₂(g) |
| CaCO₃ | CaCO₃(s) + 2HCl(aq) → CaCl₂(aq) + H₂O(l) + CO₂(g) | CaCO₃(s) + H₂SO₄(aq) → CaSO₄(aq) + H₂O(l) + CO₂(g) |
| SrCO₃ | SrCO₃(s) + 2HCl(aq) → SrCl₂(aq) + H₂O(l) + CO₂(g) | SrCO₃(s) + H₂SO₄(aq) → SrSO₄(aq) + H₂O(l) + CO₂(g) |
| BaCO₃ | BaCO₃(s) + 2HCl(aq) → BaCl₂(aq) + H₂O(l) + CO₂(g) | BaCO₃(s) + H₂SO₄(aq) → BaSO₄(aq) + H₂O(l) + CO₂(g) |
6. Group 2 Element Reactions with Acids:
| Group 2 Element | Reaction with Dilute HCl | Reaction with Dilute H₂SO₄ |
|---|---|---|
| Mg | Mg(s) + 2HCl(aq) → MgCl₂(aq) + H₂(g) | Mg(s) + H₂SO₄(aq) → MgSO₄(aq) + H₂(g) |
| Ca | Ca(s) + 2HCl(aq) → CaCl₂(aq) + H₂(g) | Ca(s) + H₂SO₄(aq) → CaSO₄(aq) + H₂(g) |
| Sr | Sr(s) + 2HCl(aq) → SrCl₂(aq) + H₂(g) | Sr(s) + H₂SO₄(aq) → SrSO₄(aq) + H₂(g) |
| Ba | Ba(s) + 2HCl(aq) → BaCl₂(aq) + H₂(g) | Ba(s) + H₂SO₄(aq) → BaSO₄(s) + H₂(g) |
7. Group 2 Element Reactions:
| Reaction with Oxygen | Reaction with Water |
|---|---|
| 2Mg(s) + O₂(g) → 2MgO(s) | Mg(s) + H₂O(l) → Mg(OH)₂ + H₂(g) |
| 2Ca(s) + O₂(g) → 2CaO(s) | Ca(s) + 2H₂O(l) → Ca(OH)₂(aq) + H₂(g) |
| 2Sr(s) + O₂(g) → 2SrO(s) | Sr(s) + 2H₂O(l) → Sr(OH)₂(s) + H₂(g) |
| 2Ba(s) + O₂(g) → 2BaO(s) | Ba(s) + 2H₂O(l) → Ba(OH)₂(s) + H₂(g) |
8. Reactions of Halogens:
| Equation for Reaction | Description of Reaction |
|---|---|
| H₂(g) + F₂(g) → 2HF(g) | Reacts explosively even in cool, dark conditions |
| H₂(g) + Cl₂(g) → 2HCl(g) | Reacts explosively in sunlight |
| H₂(g) + Br₂(g) → 2HBr(g) | Reacts slowly on heating |
| H₂(g) + I₂(g) → 2HI(g) | Forms an equilibrium mixture on heating |
9. Reactions of Metals with Chlorine:
| Metal | Chemical Equation | Reaction Conditions | Reaction |
|---|---|---|---|
| Na | 2Na(s) + Cl₂(g) → 2NaCl(s) | Heated | Vigorously |
| Mg | Mg(s) + Cl₂(g) → MgCl₂(s) | Heated | Vigorously |
| Al | 2Al(s) + 3Cl₂(g) → Al₂Cl₆(s) | Heated | Vigorously |
| Si | Si(s) + 2Cl₂(g) → SiCl₄(l) | Heated | Slowly |
| P | 2P(s) + 5Cl₂(g) → 2PCl₅(l) | Heated, Excess chlorine | Slowly |
10. Halide Ion Reactions with Silver Nitrate and Ammonia:
| Halide Ion | Colour of Silver Halide Solution | Effect of Adding Dilute Ammonia Solution to Precipitate | Effect of Adding Concentrated Ammonia Solution to Precipitate |
|---|---|---|---|
| Cl⁻ (aq) | White | Dissolves | Dissolves |
| Br⁻ (aq) | Cream | Remains insoluble | Dissolves |
| I⁻ (aq) | Pale yellow | Remains insoluble | Remains insoluble |
11.Chlorine Reactions and Uses:
| Condition | Reaction | Ionic Equation | Comments |
|---|---|---|---|
| Chlorine in cold alkali (15°C) | Cl₂ (aq) + 2NaOH (aq) → NaCl (aq) + NaClO (aq) + H₂O (l) | Cl₂ (aq) + 2OH⁻ (aq) → Cl⁻ (aq) + ClO⁻ (aq) + H₂O (l) |
The chlorine undergoes disproportionation, getting both oxidised and reduced. |
| Chlorine in hot alkali (70°C) | 3Cl₂ (aq) + 6NaOH (aq) → 5NaCl (aq) + NaClO₃ (aq) + 3H₂O (l) | 3Cl₂ (aq) + 6OH⁻ (aq) → 5Cl⁻ (aq) + ClO₃⁻ (aq) + 3H₂O (l) | |
| Chlorine in Water Purification | Cl₂ (aq) + H₂O (l) → HCl (aq) + HClO (aq) |
Cl₂ (aq) + H₂O (l) → HCl (aq) + HClO (aq) HClO (aq) → H⁺ (aq) + ClO⁻ (aq) |
The chlorine undergoes disproportionation, getting both oxidised and reduced. Chloric(I) acid (HClO) and ClO⁻ (aq) sterilise water by killing bacteria. |
12. Halide Ion Reactions with Concentrated Sulfuric Acid:
| Halide Ion | Reaction with Concentrated Sulfuric Acid | Observations |
|---|---|---|
| Cl⁻ (aq) | H₂SO₄(l) + NaCl(s) → HCl(g) + NaHSO₄(s) | White fumes of HCl gas |
| Br⁻ (aq) | H₂SO₄(l) + NaBr(s) → HBr(g) + NaHSO₄(s) H₂SO₄(l) + 2HBr(s) → Br₂(g) + SO₂(g) + 2H₂O(l) |
Reddish brown gas of Br₂ |
| I⁻ (aq) | H₂SO₄(l) + NaI(s) → HI(g) + NaHSO₄(s) 2HI(g) + H₂SO₄(l) → I₂(g) + SO₂(g) + 2H₂O(l) 6HI(g) + H₂SO₄(l) → 3I₂(g) + S(s) + 4H₂O(l) 8HI(g) + H₂SO₄(l) → 4I₂(g) + H₂S(g) + 4H₂O(l) |
Violet/purple vapour of I₂ Yellow solid of S Strong, bad smell of H₂S |