CBSE Chemistry Class 12:
Formulas, Reactions & AI Tools
Physical chemistry formulas (Nernst, Faraday, Arrhenius), all 15 name reactions the boards test, and AI tools to generate Chemistry flashcards from your notes in seconds.
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Solutions (Colligative Properties)
- ΔT_b = i·K_b·m
- ΔT_f = i·K_f·m
- Osmotic pressure: Π = iCRT
- Raoult: p_A = p°_A · x_A
- Molar mass: M = 1000K_f·w_B/(ΔT_f·w_A)
Electrochemistry
- E°cell = E°cath − E°anode
- Nernst (298K): E = E° − (0.0591/n)logQ
- ΔG° = −nFE° = −RT lnK
- Λ_m = (κ × 1000) / c
- Faraday: moles = It/(nF)
Chemical Kinetics
- Rate = k[A]^x[B]^y
- 1st order: k = (2.303/t)log([A₀]/[A])
- t₁/₂ = 0.693/k (1st order)
- Arrhenius: k = Ae^(−Ea/RT)
- log(k₂/k₁)=(Ea/2.303R)(1/T₁−1/T₂)
The 15 reactions you must know cold
| Reaction | What happens | Reagents / condition |
|---|---|---|
| Aldol condensation | Carbonyl with α-H → β-hydroxy carbonyl → dehydration | Base catalyst (NaOH) |
| Cannizzaro reaction | Non-α-H aldehyde → disproportionation (acid + alcohol) | Conc. NaOH, e.g. HCHO |
| Clemmensen reduction | C=O → CH₂ (acidic conditions) | Zn/Hg + HCl |
| Wolff–Kishner reduction | C=O → CH₂ (basic conditions) | N₂H₄ + KOH/ethylene glycol |
| Reimer–Tiemann | Phenol → ortho-hydroxybenzaldehyde | CHCl₃ + NaOH |
| Kolbe's reaction | Sodium phenoxide + CO₂ → salicylic acid | High pressure, heat |
| Hofmann bromamide | Amide → 1° amine (loses one carbon) | Br₂ + NaOH |
| Gabriel synthesis | Phthalimide → 1° amine only | RX then hydrolysis |
| Hinsberg test | Distinguishes 1°, 2°, 3° amines | C₆H₅SO₂Cl (benzenesulphonyl chloride) |
| Sandmeyer reaction | Diazonium salt → Cl/Br/CN substituted arene | CuCl or CuBr or CuCN |
| Balz–Schiemann | Diazonium → fluorobenzene | HBF₄ then heat |
| Diazotisation | 1° aromatic amine → diazonium salt | NaNO₂ + HCl, 0–5°C |
| Lucas test | Distinguishes 1°, 2°, 3° alcohols by speed | ZnCl₂ + conc. HCl |
| Iodoform test | CH₃CO- group → CHI₃ (yellow ppt) | I₂ + NaOH |
| Fehling's / Tollens' | Aldehyde (not ketone) → positive result | Fehling solution or Tollen's reagent |
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Nernst equation temperature trap
The 0.0591/n shortcut is ONLY valid at exactly 298 K (25°C). At any other temperature, the full form is 2.303RT/nF. Boards test this directly.
Molarity vs molality
Molarity changes with temperature (volume changes). Molality and mole fraction do NOT change with temperature. Use molality in colligative property formulas.
Order ≠ molecularity
Order is determined experimentally from rate data. Molecularity is theoretical (number of molecules in the rate-determining step). Never assume order from the balanced equation.
Anode and cathode confusion
AN OX: Anode = Oxidation. RED CAT: Cathode = Reduction. True in both galvanic cells AND electrolytic cells — just remember the sign changes (galvanic: anode is −; electrolytic: anode is +).