Theoretical Principles of Experimental Chemistry
Complete Formula Sheet & Shortcut Bible · BITSAT 2026
CrackIt
Core Volumetric Analysis Formulas
Molarity (M)
M = Moles of Solute
────────────────
Volume of Solution (L)
────────────────
Volume of Solution (L)
Normality (N)
N = Gram Equivalents
────────────────
Volume of Solution (L)
────────────────
Volume of Solution (L)
Molarity & Normality
Normality = Molarity × n-factor
n-factor is valency, acidity, basicity, or change in oxidation number.
Dilution Law
M₁V₁ = M₂V₂
N₁V₁ = N₂V₂
N₁V₁ = N₂V₂
Initial concentration & volume equals final concentration & volume.
Molarity of Mixing
Mfinal = M₁V₁ + M₂V₂
──────────
V₁ + V₂
──────────
V₁ + V₂
For non-reacting solutions.
Strength (g/L)
Strength = Molarity × Molar Mass
Strength = Normality × Eq. Wt.
Strength = Normality × Eq. Wt.
Titration & Stoichiometry
General Titration Equation
n₁M₁V₁ = n₂M₂V₂
where n = stoichiometric coefficient ratio
where n = stoichiometric coefficient ratio
A more fundamental form is (M₁V₁)/n₁ = (M₂V₂)/n₂ for reaction aA + bB → cC + dD.
Equivalent Weight (Eq. Wt.)
Eq. Wt. = Molar Mass
──────────
n-factor
──────────
n-factor
Crucial for normality calculations and redox titrations.
n-factor (Redox)
n-factor = Total change in
Oxidation Number per mole
Oxidation Number per mole
For KMnO₄ (acidic) n=5; K₂Cr₂O₇ (acidic) n=6.
% Purity
% Purity = Mass of Pure Substance
─────────────── × 100
Mass of Impure Sample
─────────────── × 100
Mass of Impure Sample
Key Inorganic Qualitative Tests
Flame Test Colors
Li: Crimson Red
Na: Golden Yellow
K: Lilac (Pale Violet)
Ca: Brick Red
Sr: Crimson
Ba: Apple Green
Cu: Blue-Green
Na: Golden Yellow
K: Lilac (Pale Violet)
Ca: Brick Red
Sr: Crimson
Ba: Apple Green
Cu: Blue-Green
Brown Ring Test (NO₃⁻)
FeSO₄(aq) + conc. H₂SO₄
Forms [Fe(H₂O)₅NO]SO₄ at the junction of two liquids.
Forms [Fe(H₂O)₅NO]SO₄ at the junction of two liquids.
Confirmatory test for Nitrate ion.
Chromyl Chloride Test (Cl⁻)
Salt + K₂Cr₂O₇ + conc. H₂SO₄ → CrO₂Cl₂ (Reddish-brown fumes)
Confirmatory test for Chloride ion. Br⁻ and I⁻ do not give this test.
Nessler's Reagent Test (NH₄⁺)
Reagent: K₂[HgI₄]
Forms Brown Precipitate (Iodide of Millon's base).
Forms Brown Precipitate (Iodide of Millon's base).
Extremely sensitive test for ammonium ions.
Borax Bead Test
Na₂B₄O₇ → 2NaBO₂ + B₂O₃
CuO + B₂O₃ → Cu(BO₂)₂ (Blue bead)
CuO + B₂O₃ → Cu(BO₂)₂ (Blue bead)
Used to identify transition metal cations like Cu²⁺, Co²⁺, Ni²⁺.
BITSAT Lab Hacks & Shortcuts
Precipitate Colors: Most sulfides (PbS, CuS) are black. ZnS is white. CdS is yellow.
Gas Identification: Rotten egg smell → H₂S. Pungent smell → NH₃. Colorless, turns brown in air → NO.
Flame Test Mnemonics: Think of brands or phrases. 'Na-Yellow' sounds like 'Nay, hello!'. 'Ba-Green' for Barium.
Solubility Rule: 'NAG SAG' - Nitrates (NO₃⁻), Acetates (CH₃COO⁻), Group 1 are always soluble. Sulfates (SO₄²⁻), Ammonium (NH₄⁺), Group 17 (halides) are generally soluble.
For redox titrations, quickly find n-factors for common agents: MnO₄⁻ → Mn²⁺ (n=5), Cr₂O₇²⁻ → 2Cr³⁺ (n=6), C₂O₄²⁻ → 2CO₂ (n=2).
Purification & Separation Techniques
Fractional Distillation
Separates liquids with small difference in boiling points (< 25 K).
Principle: Vapors of the more volatile liquid rise higher in the fractionating column. Ex: Crude oil refining.
Steam Distillation
For substances that are steam volatile and immiscible with water.
Boils when sum of vapor pressures equals atmospheric pressure. Purifies liquids below their normal boiling point. Ex: Aniline.
Chromatography (Rբ Value)
Rf = Distance travelled by Solute
───────────────────
Distance travelled by Solvent
───────────────────
Distance travelled by Solvent
Retention factor. Always less than 1. Higher Rբ means less adsorption to stationary phase.
Distinguishing Tests for Organic Compounds
| Test Name | Reagent(s) | Positive For | Key Observation |
|---|---|---|---|
Tollen's Test | Ammoniacal AgNO₃ (Tollen's Reagent) | Aldehydes, α-hydroxy ketones | Silver mirror or black precipitate |
Fehling's Test | Fehling's Soln. A (CuSO₄) + B (Rochelle Salt) | Aliphatic Aldehydes | Reddish-brown precipitate of Cu₂O |
Lucas Test | Anhydrous ZnCl₂ + conc. HCl | Alcohols (distinguishes 1°, 2°, 3°) | Turbidity: Immediate (3°), after 5-10 mins (2°), on heating (1°) |
Iodoform Test | I₂ + NaOH (or NaOI) | Methyl ketones, Acetaldehyde, Ethanal, 2° Alcohols with CH₃CH(OH)- group | Yellow precipitate of CHI₃ (Iodoform) |
Ferric Chloride Test | Neutral FeCl₃ solution | Phenols, Enols | Violet, blue, green, or red coloration |