Class 12 Chemistry Formulas Handbook (Chapter-wise)

Every key formula and result from the Class 12 Chemistry NCERT syllabus, organised by chapter, in one place. Cross-linked to our full Chapter-wise Solutions. More chapters will be appended here as their Solutions are published.

Class 12 Chemistry Formulas Handbook

Chapter 1: The Solid State

• Density formula: d = ZM/(a³N_A)
• Packing efficiency: simple cubic 52.4%, bcc 68%, ccp/hcp 74%
• Coordination number: simple cubic=6, bcc=8, ccp/hcp=12
• Void radius ratios: tetrahedral r/R≈0.225, octahedral r/R≈0.414
• Voids in close packing: tetrahedral = 2n, octahedral = n (n=number of spheres)
• Edge length relations: simple cubic a=2r; bcc √3a=4r; fcc √2a=4r
• See full Chapter 1 Solutions

Chapter 2: Solutions

• Mass % = (mass of component ÷ total mass of solution) × 100
• Volume % = (volume of component ÷ total volume of solution) × 100
• Mass by volume % = (mass of solute in g ÷ volume of solution in mL) × 100
• ppm = (amount of component ÷ total amount of solution) × 10^6
• Mole fraction: x_A = n_A ÷ (n_A + n_B)
• Molarity: M = moles of solute ÷ volume of solution (L)
• Molality: m = moles of solute ÷ mass of solvent (kg)
• Henry’s law: p = K_H · x
• Raoult’s law (volatile solute): p1 = x1 p°1; p_total = x1 p°1 + x2 p°2
• Raoult’s law (non-volatile solute): (p°−p) ÷ p° = x2 (relative lowering of vapour pressure)
• Elevation of boiling point: ΔTb = i · Kb · m
• Depression of freezing point: ΔTf = i · Kf · m
• Osmotic pressure: π = i · C · R · T
• Van’t Hoff factor: i = normal molar mass ÷ observed molar mass = observed colligative property ÷ calculated colligative property
• Van’t Hoff factor (dissociation into n ions): i = 1 + (n−1)α
• Van’t Hoff factor (association into n-mer): i = 1 − α(1 − 1/n)

See full Chapter 2 Solutions NCERT Solutions.

Written by Satish

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