XII CHEMISTRY - VOLUME I
Interactive Core Concepts, Allotropes, and Coordination Compounds
The sulphur dioxide produced during roasting process is harmful to the environment. In modern metallurgical factories, this by-product is trapped and converted into sulphuric acid to avoid air pollution.
Principal Ores of Key Metals
| Metal | Ores | Composition |
|---|---|---|
| Aluminum | Bauxite, Diaspore, Kaolinite | Al₂O₃.nH₂O, Al₂O₃.H₂O, Al₂Si₂O₅(OH)₄ |
| Iron | Haematite, Magnetite, Siderite, Iron pyrite, Limonite | Fe₂O₃, Fe₃O₄, FeCO₃, FeS₂, Fe₂O₃.3H₂O |
| Copper | Copper pyrite, Copper glance, Cuprite, Malachite, Azurite | CuFeS₂, Cu₂S, Cu₂O, CuCO₃.Cu(OH)₂, 2CuCO₃.Cu(OH)₂ |
| Zinc | Zinc blende (Sphalerite), Calamine, Zincite | ZnS, ZnCO₃, ZnO |
| Lead | Galena, Anglesite, Cerrusite | PbS, PbSO₄, PbCO₃ |
| Silver | Silver glance (Argentite), Pyrargyrite (Ruby silver), Chlorargyrite (Horn Silver), Stefinite, Proustite | Ag₂S, Ag₃SbS₃, AgCl, Ag₅SbS₄, Ag₃AsS₃ |
| Tin | Cassiterite (Tin stone) | SnO₂ |
Common Allotropes of Elements
Carbon
Diamond, Graphite, Graphene, Fullerenes, Carbon nanotubes
Phosphorus
White phosphorus, Red phosphorus, Scarlet phosphorus, Violet phosphorus, Black phosphorus
Boron
Amorphous boron, α-rhombohedral boron, β-rhombohedral boron, γ-orthorhombic boron, α-tetragonal boron, β-tetragonal boron
Sulphur
Rhombic sulphur, Monoclinic sulphur
Oxygen
Dioxygen, Ozone
Tin
Grey tin, white tin, rhombic tin, sigma tin
Properties of Halogen Hydrides
| Property | Trend / Order |
|---|---|
| Reactivity of hydrogen | Decreases from fluorine to iodine |
| Stability | Decreases from HF to HI |
| Thermal stability | HF > HCl > HBr > HI |
| Volatility of hydrides | HF < HI < HBr < HCl |
| Boiling point | HCl < HBr < HI < HF |
| Acid strength | Increases from HF to HI |
Oxoacids of Phosphorus
| Name | Formula | Oxidation State | Preparation Reaction |
|---|---|---|---|
| Hypophosphorous acid | H₃PO₂ | +1 | P₄ + 6H₂O → 3H₃PO₂ + PH₃ |
| Orthophosphorous acid | H₃PO₃ | +3 | P₄O₆ + 6H₂O → 4H₃PO₃ |
| Hypophosphoric acid | H₄P₂O₆ | +4 | 2P + 2O₂ + 2H₂O → H₄P₂O₆ |
| Orthophosphoric acid | H₃PO₄ | +5 | P₄O₁₀ + 6H₂O → 4H₃PO₄ |
| Pyrophosphoric acid | H₄P₂O₇ | +5 | 2H₃PO₄ → H₄P₂O₇ + H₂O |
Cisplatin (cis-[Pt(NH₃)₂Cl₂]) is a square planar coordination complex where similar ligands occupy adjacent positions. It is a vital platinum-based anticancer drug that undergoes hydrolysis and bonds with DNA inside cells, producing crosslinks that stop DNA replication and transcription, ultimately inducing cancer cell death.
Interhalogen & Xenon Compound Geometries
| Compound Type / Formula | Hybridisation | Shape / Structure | Bond Pairs / Lone Pairs |
|---|---|---|---|
| AX (e.g., XeF₂) | sp³d | Linear | 1/3 (or 2/3 for XeF₂) |
| AX₃ (e.g., XeOF₂, ClF₃) | sp³d | T-shaped | 3/2 |
| AX₅ (e.g., XeOF₄) | sp³d² | Square pyramidal | 5/1 |
| AX₇ (e.g., IF₇) | sp³d³ | Pentagonal bipyramidal | 7/0 |
| XeF₄ | sp³d² | Square planar | - |
| XeF₆ | sp³d³ | Distorted octahedron | - |
| XeO₃ | sp³ | Pyramidal | - |
IUPAC Nomenclature Nomenclature Reference
| Coordination Formula | IUPAC System Name |
|---|---|
| [Ag(NH₃)₂]Cl | Diamminesilver(I) chloride |
| [Co(en)₂Cl₂]Cl | Dichloridobis(ethane-1,2-diamine)cobalt(III) chloride |
| [Cu(NH₃)₄]SO₄ | Tetraamminecopper(II) sulphate |
| K₄[Fe(CN)₆] | Potassium hexacyanido-κCferrate(II) |
Pharmacokinetics & Half-Life
Chemical kinetics helps evaluate drug lifetime metrics (bioavailability) inside human tissue. For instance, Paracetamol has a biological half-life of 2.5 hours. Every 2.5 hours, its systemic concentration drops by half. After 10 hours (4 half-lives), only 6.25% of the original dose remains in the system.
General Integrated Rate Law
For an nth order reaction (n ≠ 1) containing one reactant:
1/[A]^(n-1) - 1/[A₀]^(n-1) = (n-1)kt
Half-life expression:
t₁/₂ = (2^(n-1) - 1) / ((n-1)k[A₀]^(n-1))
KMnO₄ Equivalent Weights
- Acid Medium: 158 / 5 = 31.6 (5 electrons transferred)
- Neutral Medium: 158 / 3 = 52.67 (3 electrons transferred)
- Basic Medium: 158 / 1 = 158.0 (1 electron transferred)
Standing over 23 feet high and weighing upwards of 6000 kg, this 1600-year-old iron marvel resists environmental corrosion due to a unique configuration of raw unreduced iron mixed with atmospheric cycling. This created a thin, protective surface layer of misawite (a structural compound consisting of iron, oxygen, and hydrogen atoms) preventing standard rust degradation patterns.