Interactive +2 Chemistry Minimum Study Guide

XII Standard Chemistry

"Chemistry is not just a subject, it's a way of thinking!"

Important Inorganic Equations

1. Mond's Process for Refining Nickel Inorganic

Nickel is heated with carbon monoxide to form a volatile complex, which decomposes at higher temperatures to yield pure nickel.

Ni + 4 CO —(350 K)→ Ni(CO)₄ —(460 K)→ Ni + 4 CO

2. Van-Arkel Method for Refining Titanium Inorganic

Crude titanium is heated with iodine to form volatile titanium tetraiodide, which is then decomposed on a hot tungsten filament.

Ti + 2 I₂ —(550 K)→ TiI₄ —(1800 K)→ Ti + 2 I₂

3. Auto Reduction Inorganic

Cinnabar ore (HgS) is heated with air to directly yield liquid mercury without an external reducing agent.

HgS + O₂ → Hg + SO₂

4. Aluminothermic Process Inorganic

Chromic oxide is mixed with aluminium powder and ignited to produce molten chromium metal.

Cr₂O₃ + 2 Al → 2 Cr + Al₂O₃
BaO₂ + Mg → BaO + MgO (Ignition mixture ignition step)

5. Preparation of Inorganic Benzene Inorganic

Diborane reacts with ammonia in a closed vessel at elevated temperatures to form Borazine (Inorganic Benzene).

3 B₂H₆ + 6 NH₃ → 2 B₃N₃H₆ + 12 H₂

Interactive Self-Check: Calcination

What happens during the calcination of Calcium Carbonate?

Answer: Concentrated ore is heated strongly in the absence of air.

CaCO₃ —(Heat)→ CaO + CO₂

Core Laws and Derivations

Ostwald's Dilution Law Physical

For a weak acid binary electrolyte like acetic acid undergoing dissociation:

CH₃COOH ∃ H⁺ + CH₃COO^-

Species	CH₃COOH	H⁺	CH₃COO^-
Initial	C	0	0
Change	-αC	+αC	+αC
Equilibrium	(1-α)C	αC	αC

Equilibrium Constant expression:

K_a = (αC)(αC) / (1-α)C = α²C / (1-α)

Since α << 1 for weak electrolytes, (1 - α) ≈ 1. Therefore:

K_a = α²C ⇒ α = √(K_a / C)

Nernst Equation Physical

For a general redox reaction: xA + yB ∃ lC + mD

Using ΔG = ΔG° + RT ln Q, where ΔG = -nFE and ΔG° = -nFE°:

E_cell = E°_cell - (RT/nF) ln([C]^l[D]^m / [A]^x[B]^y)

At 298 K, converting to common logarithm:

E_cell = E°_cell - (0.0591 / n) log₁₀([C]^l[D]^m / [A]^x[B]^y)

Integrated Rate Law: First Order Reaction Physical

Reaction: A → Products

Rate = -d[A]/dt = k[A]¹ ⇒ -d[A]/[A] = k dt

Integrating from t=0 ([A₀]) to t=t ([A]):

ln([A₀]/[A]) = kt ⇒ k = (2.303 / t) log₁₀([A₀]/[A])

Comparative Chemistry Matrix

Schottky Defect vs Frenkel Defect

Schottky Defect	Frenkel Defect
Arises due to missing of equal number of cations and anions from crystal lattice.	Arises due to dislocation of an ion from its lattice site to an interstitial position.
Lowers the overall density of the crystal.	Does not alter the density of the crystal.
Observed when cation and anion are of similar sizes (e.g., NaCl).	Observed when sizes of cation and anion differ significantly (e.g., AgBr).

Physisorption vs Chemisorption

Physisorption	Chemisorption
Instantaneous and non-specific.	Very slow process and highly specific.
Low heat of adsorption.	High heat of adsorption.
Forms multi-molecular layers of adsorbate.	Forms a mono-molecular layer of adsorbate.
No electron transfer occurs.	Involves transfer/sharing of electrons.

DNA vs RNA

DNA	RNA
Contains Deoxyribose sugar.	Contains Ribose sugar.
Double-stranded framework; highly stable and long-lived.	Single-stranded framework; unstable and short-lived.
Base pairing components: A=T and G≡C.	Base pairing components: A=U and G≡C.

Core High-Yield Concepts

Bayer's Reagent

Definition: Cold alkaline KMnO₄ solution.

Used to detect unsaturation in organic compounds by converting ethylene into ethylene glycol.

CH₂=CH₂ + HOH + [O] → HOCH₂-CH₂OH

Common Ion Effect

The degree of dissociation of a weak electrolyte is suppressed by adding a strong electrolyte containing a common ion.

Example: The dissociation of acetic acid (CH₃COOH) drops upon adding sodium acetate (CH₃COONa).

Catenation Conditions

The unique ability of an element to form long atomic chains via self-bonding.

Valency of the element must be ≥ 2.
The element must possess strong self-bonding capability.

Coordination Numbers & Solids

Coordination Number of BCC: 8
Packing Efficiencies: Simple Cubic (SC) = 52.3%, Body-Centered Cubic (BCC) = 68%, Face-Centered Cubic (FCC) = 74%.
Bragg's Equation: nλ = 2d sinθ

Industrial and Medical Applications

Chemical Entity / Element	Major Practical Applications
Silicones	Low-temperature lubricants, vacuum pump fluids, high-temperature oil baths, and waterproof textile coatings.
Helium (He)	Cryogenics, filling high-altitude meteorological balloons, and deep-sea diving breathing mixtures (He-O₂).
Cisplatin	Highly effective coordination compound used as an anticancer drug.
Glycerol	Sweetening agent in foodstuffs, cosmetic formulation ingredient, and synthesis of explosives like Trinitroglycerine (TNG).
Urotropine	Used therapeutically for treating urinary tract infections and industrially to manufacture the explosive RDX.
Formaldehyde (HCHO)	40% solution (Formalin) acts as a preservative for biological specimens; also used in leather tanning and Bakelite synthesis.

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Interactive +2 Chemistry Revision Guide: Equations & Laws