PYQ Vault

Reference

The 49 reactions and formulas MHT-CET Chemistry actually tests

One page, grouped by chapter in strand order. The Calculate chapters carry their formulas, the Reactions chapters their named reactions and reagents, the Recall chapters their tables. At about 40 seconds a Chemistry question, a reaction you have to work out in the hall is time Physics does not get.

reactions and formulas
49
chapters covered
20
a question, Paper II average
0.9 min
papers of PYQs behind it
42

How to use this page

  • First read: cover-to-cover, marking every line you don’t already know cold. The groups follow the strategy strands — Calculate, then Reactions, then Recall.
  • Learn reactions both ways: the paper asks for the product from a reagent AND the reagent from a product. Clemmensen and Wolff–Kishner give the same product from opposite conditions; Finkelstein and Swarts differ in one halide. The look-alike is always an option.
  • Active recall: cover the right-hand side, read only the NAME, and write the reaction or formula from memory. Anything you miss goes on tomorrow’s list. Each chapter header links to its playbook, which is where you find out how the paper uses it.

Solutions and Colligative Properties

Playbook

  • Colligative properties

    ΔT_b = i·K_b·m ΔT_f = i·K_f·m π = i·C·R·T (p° − p)/p° = x₂

    m = molality
    C = molarity
    i = van't Hoff factor

    Note:i = 2 for NaCl, 3 for CaCl₂, 4 for AlCl₃ (full dissociation).

  • Henry's law

    C = K_H · p

    C = solubility of the gas
    p = its partial pressure

Solid State

Playbook

  • Density of a unit cell

    ρ = z·M / (a³·N_A)

    z = 1 (sc), 2 (bcc), 4 (fcc)
    a in cm

  • Radius and edge

    sc: r = a/2 bcc: r = √3·a/4 fcc: r = √2·a/4

    a = edge length

  • Packing and voids

    sc 52.4% bcc 68% fcc/hcp 74% n atoms → n octahedral, 2n tetrahedral voids

Chemical Kinetics

Playbook

  • First-order kinetics

    k = (2.303/t)·log(a/(a − x)) t½ = 0.693/k

    a = initial amount
    x = amount reacted

    Note:log 2 = 0.301, log 3 = 0.477, log 5 = 0.699 — no calculator.

  • Zero-order kinetics

    [A] = [A]₀ − kt t½ = [A]₀ / 2k

  • Arrhenius

    log(k₂/k₁) = (Eₐ / 2.303R)·(1/T₁ − 1/T₂)

    Eₐ = activation energy

Ionic Equilibria

Playbook

  • pH

    pH = −log[H⁺] pH + pOH = 14 (25 °C)

  • Weak electrolytes

    α = √(K/c) [H⁺] = √(Ka·c)

    α = degree of dissociation

  • Buffer

    pH = pKa + log([salt]/[acid])

  • Solubility product

    AB: s² AB₂: 4s³ A₂B₃: 108s⁵

    s = molar solubility

Chemical Thermodynamics and Energetics

Playbook

  • First law

    ΔU = q + w w = −P_ext·ΔV 1 dm³ bar = 100 J

    Work done ON the system is positive

  • ΔH and ΔU

    ΔH = ΔU + Δn_g·R·T

    Δn_g = gas moles of products − reactants

  • Gibbs energy

    ΔG = ΔH − TΔS ΔG° = −2.303RT·log K equilibrium T = ΔH/ΔS

Electrochemistry

Playbook

  • Cell potential and energy

    E°cell = E°cathode − E°anode ΔG° = −n·F·E°

    reduction potentials for both

  • Nernst equation (25 °C)

    E = E° − (0.0592/n)·log Q

    n = electrons transferred

  • Conductivity

    κ = cell constant / R Λm = 1000·κ / c α = Λm / Λ°m

    Λm in S cm² mol⁻¹

  • Faraday's law

    m = (M / n·F)·I·t 1 F = 96500 C

Structure of Atom

Playbook

  • Bohr model

    r = 0.529·n²/Z Å E = −13.6·Z²/n² eV

  • Radiation and matter waves

    E = h·ν = h·c/λ λ = h/(m·v)

Some Basic Concepts of Chemistry

Playbook

  • The mole

    n = m/M = N/N_A = V/22.4 dm³ (gas at STP)

    N_A = 6.022 × 10²³

  • Concentration

    molarity = mol / L solution molality = mol / kg solvent

Alcohols, Phenols and Ethers

Playbook

  • Lucas test

    ZnCl₂/conc. HCl: 3° turbid at once · 2° in minutes · 1° not at room temperature

  • Phenol named reactions

    Reimer–Tiemann: phenol + CHCl₃/NaOH → salicylaldehyde Kolbe: sodium phenoxide + CO₂ → salicylic acid

  • Williamson ether synthesis

    R–O⁻Na⁺ + R′–X → R–O–R′

    R′–X should be primary

Aldehydes, Ketones and Carboxylic Acids

Playbook

  • Making aldehydes

    Rosenmund: RCOCl + H₂ (Pd/BaSO₄) → RCHO Stephen: RCN + SnCl₂/HCl → RCHO Etard: toluene + CrO₂Cl₂ → benzaldehyde

  • C=O to CH₂

    Clemmensen: Zn–Hg / conc. HCl Wolff–Kishner: NH₂NH₂ / KOH

  • Tests

    Tollens' → silver mirror (aldehydes) Fehling's → red Cu₂O iodoform: CH₃CO– or CH₃CH(OH)–

  • Aldol and Cannizzaro

    Aldol: needs α-H Cannizzaro: no α-H (HCHO, C₆H₅CHO) → alcohol + acid salt

Amines

Playbook

  • Basicity in water

    (CH₃)₂NH > CH₃NH₂ > (CH₃)₃N > NH₃ > C₆H₅NH₂

  • Hofmann bromamide

    RCONH₂ + Br₂ + 4NaOH → RNH₂ (one carbon fewer)

  • Diazonium salts

    C₆H₅NH₂ + NaNO₂/HCl (273 K) → C₆H₅N₂⁺Cl⁻ → phenol (H₂O, Δ) · C₆H₅Cl (CuCl, Sandmeyer)

Halogen Derivatives of Alkanes

Playbook

  • Halide exchange

    Finkelstein: RCl/RBr + NaI (acetone) → RI Swarts: RCl + AgF → RF

  • Coupling

    Wurtz: 2RX + 2Na → R–R Fittig: 2ArX + 2Na → Ar–Ar Wurtz–Fittig: ArX + RX + 2Na → Ar–R

  • Substitution against elimination

    aq. KOH → alcohol alc. KOH → alkene (Saytzeff: more substituted) 3° SN1, 1° SN2

Aromatic Compounds

Playbook

  • Aromaticity

    planar · cyclic · conjugated · (4n + 2) π electrons

  • Directing groups

    o/p: –OH –NH₂ –R –X m: –NO₂ –CN –CHO –COOH

Alkanes

Playbook

  • Decarboxylation

    RCOONa + NaOH (CaO, Δ) → R–H + Na₂CO₃

    one carbon fewer

  • Grignard to alkane

    RMgX + H₂O → R–H

Biomolecules

Playbook

  • Glycosidic linkages

    sucrose α1–β2 (non-reducing) · maltose α1–4 · lactose β1–4 · cellulose β1–4 · starch α1–4 + α1–6

  • Nucleic acid bases

    DNA: A G C T + deoxyribose RNA: A G C U + ribose

Coordination Compounds

Playbook

  • Effective atomic number

    EAN = Z − oxidation state + 2 × coordination number

  • Denticity

    mono: NH₃ H₂O Cl⁻ CN⁻ bi: en ox²⁻ hexa: EDTA⁴⁻

Introduction to Polymer Chemistry

Playbook

  • Monomers

    nylon 6,6: hexamethylenediamine + adipic acid · nylon 6: caprolactam · Buna-S: butadiene + styrene · Buna-N: butadiene + acrylonitrile · terylene: ethylene glycol + terephthalic acid · bakelite: phenol + formaldehyde

Transition and Inner Transition Elements

Playbook

  • Spin-only magnetic moment

    μ = √(n(n + 2)) BM n = 1→1.73 · 2→2.83 · 3→3.87 · 4→4.90 · 5→5.92

    n = unpaired electrons

Chemical Bonding and Molecular Structure

Playbook

  • Bond order

    bond order = (bonding − antibonding electrons) / 2 N₂ 3 · O₂ 2 · O₂⁻ 1.5 · O₂²⁻ 1

  • VSEPR

    steric number 2 linear · 3 trigonal planar · 4 tetrahedral · 5 trigonal bipyramidal · 6 octahedral

    lone pairs bend the shape

Surface Chemistry

Playbook

  • Hardy–Schulze rule

    negative sol: Al³⁺ > Ba²⁺ > Na⁺ positive sol: [Fe(CN)₆]⁴⁻ > SO₄²⁻ > Cl⁻

    the ion opposite in charge to the sol coagulates it

Why plain text (not typeset)

Everything on this page is plain text plus unicode (ρ = z·M/(a³·N_A), RCOCl + H₂ → RCHO, μ = √(n(n + 2))). Plain text means the page loads instantly, copies cleanly into your own notes, and reads correctly to a screen reader symbol by symbol. Full typesetting is reserved for the teaching notes, where you are solving rather than revising.