Chemistry
What the paper tests
The Chemistry section covers mole concept and stoichiometry, atomic structure, periodicity, chemical bonding, states of matter, thermodynamics, equilibrium (including ionic), redox, electrochemistry, representative s- and p-block elements, coordination compounds, basic organic chemistry and hydrocarbons, plus environmental and polymer chemistry. IMU CET favours numerical mole work and definition-driven recall over long mechanistic chains.
Core rules to have at your fingertips
- Mole relations: n = m/M = N/N_A = V(L)/22.4 at STP, with N_A = 6.022 × 10²³.
- Molarity M = moles of solute / litres of solution; dilution: M₁V₁ = M₂V₂.
- pH = −log[H⁺]; for a strong monobasic acid, [H⁺] equals the acid concentration.
- Hess's law and ΔG = ΔH − TΔS decide spontaneity; ΔG < 0 means spontaneous.
- Oxidation number of oxygen is −2 except in peroxides (−1) and OF₂ (+2).
- IUPAC naming: longest chain first, lowest locants, then alphabetical substituent order.
Worked example
What mass of NaOH is needed to prepare 500 mL of 0.20 M solution? (Na = 23, O = 16, H = 1) Moles required = M × V(litres) = 0.20 × 0.500 = 0.10 mol. Molar mass of NaOH = 23 + 16 + 1 = 40 g/mol. Mass = 0.10 × 40 = 4.0 g. The whole question turns on converting 500 mL to 0.500 L; substituting 500 directly inflates the answer by a factor of a thousand, which is exactly what one distractor offers.
Traps that cost marks
- Confusing moles of molecules with moles of atoms in a formula such as H₂SO₄ (4 mol of atoms per mole of acid).
- Using 22.4 L only for gases at STP, not for solutions or solids.
- Assuming a weak acid is fully dissociated when computing pH.
- Assigning oxygen a −2 state in H₂O₂ or in a peroxide linkage.
- Naming errors where the lowest locant set is chosen by first-difference rather than by the set as a whole.