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Physical chemistry is where many NEET aspirants who are strong in biology lose chemistry marks. The formulas are few, but the questions mix units, logarithms and small traps, and you have to do it all by hand. This post lists the chapters, works four typical numericals without a calculator, names the common mistakes and ends with a four-week plan.
Which physical chemistry chapters are in the NEET 2026 syllabus?
The NMC syllabus for NEET UG-2026 lists eight units under Physical Chemistry:
Some Basic Concepts in Chemistry (mole concept, stoichiometry, empirical formulae).
Atomic Structure (Bohr model, de Broglie relation, quantum numbers).
Chemical Bonding and Molecular Structure.
Chemical Thermodynamics (Hess's law, entropy, Gibbs energy).
Solutions (concentration terms, Raoult's law, colligative properties, van't Hoff factor).
Equilibrium (Kp and Kc, Le Chatelier, pH, buffers, solubility product).
Redox Reactions and Electrochemistry (Nernst equation, Kohlrausch's law).
Chemical Kinetics (rate laws, zero and first order, half-lives, Arrhenius).
Numericals appear mostly in units 1, 2 and 4 to 8; bonding questions are more about structure, shape and bond order. Check the syllabus for your exam year, since NMC notifies it afresh.
Why do you need no-calculator methods?
The NEET (UG) 2026 bulletin lists calculators and log tables among items not allowed in the exam hall. So learn log 2 = 0.301, log 3 = 0.477 and log 5 = 0.699, and the habit of writing numbers in powers of ten. Then most logs become simple: log(2 × 10^-3) = 0.301 - 3 = -2.699.
Worked example 1: freezing point depression
3.0 g of urea (molar mass 60 g/mol) is dissolved in 250 g of water. Kf for water is 1.86 K kg/mol. Find the freezing point.
Moles of urea = 3.0 / 60 = 0.050 mol.
Molality = 0.050 / 0.250 kg = 0.20 mol/kg.
Delta Tf = Kf × m = 1.86 × 0.20 = 0.372 K.
Freezing point = -0.372 °C.
Urea does not dissociate, so the van't Hoff factor is 1. The common mistake is dividing by 250 instead of 0.250 kg. The NCERT chapter Solutions uses the same Kf value of 1.86 K kg/mol for water in its worked examples.
Worked example 2: first-order half-life
A first-order reaction has k = 0.0693 per minute. What fraction remains after 30 minutes?
t1/2 = 0.693 / k = 0.693 / 0.0693 = 10 minutes. This is the relation given in the NCERT chapter Chemical Kinetics.
30 minutes = 3 half-lives.
Fraction left = (1/2)^3 = 1/8 = 12.5%.
Spot whole numbers of half-lives before reaching for the integrated rate law. A trap: the half-life of a zero-order reaction depends on the starting concentration, so this shortcut is for first order only.
Worked example 3: pH of a very dilute acid
What is the pH of 10^-8 M HCl?
The tempting answer, 8, would make an acid solution basic. At this concentration, water's own ionisation matters. The NCERT chapter Equilibrium works this exact case: setting [H3O+] = 10^-8 + x and solving with Kw = 10^-14 gives pH = 6.98, just below 7. For an ordinary case, 0.002 M HCl: pH = -log(2 × 10^-3) = 3 - 0.301 = 2.70.
Worked example 4: Nernst equation for a Daniell cell
For Zn | Zn2+ (0.01 M) || Cu2+ (1 M) | Cu, E°cell = 1.10 V and n = 2. At 298 K:
E = E° - (0.059 / n) log([Zn2+] / [Cu2+]).
log(0.01 / 1) = -2.
E = 1.10 - (0.0295 × -2) = 1.10 + 0.059 = 1.159 V, about 1.16 V.
The NCERT chapter Electrochemistry gives the Daniell cell potential as 1.1 V and uses 0.059 V for 2.303RT/F at 298 K. Watch the sign: a lower product (Zn2+) concentration raises the cell potential. Another trap is using n = 1 for a two-electron reaction.
Common mistakes and how to avoid them
Mass of solution instead of solvent in molality.
Natural log versus log base 10: ln x = 2.303 log x.
Wrong n in the Nernst equation; count electrons from the balanced half-reactions.
Units of k that do not match the order: per second for first order, mol/L per second for zero order.
Ignoring the van't Hoff factor for electrolytes such as NaCl in colligative property questions.
Rounding too early; keep one extra figure until the last step.
Our deeper guides cover colligative properties, rate laws and the Nernst equation.
A four-week practice plan
The plan uses two well-tested ideas. In a three-month classroom study with seventh-grade maths students, Rohrer, Dedrick and Stershic found that interleaved practice, where different kinds of problems are mixed so students must choose the method, produced higher scores than blocked practice on both an immediate and a delayed test. And Roediger and Karpicke showed that taking tests produced better retention after two days and a week than restudying the same material.
Week 1: one unit a day from units 1, 5 and 8; ten numericals each, formula and units written first.
Week 2: units 4, 6 and 7 the same way.
Week 3: mixed sets of 15 questions drawn from all six units, timed at about a minute each, with no headings.
Week 4: two 45-question chemistry mocks; for each wrong answer, note whether it was a concept, unit or arithmetic error, and redo it two days later.
When you get a numerical wrong and cannot see why, the Fermi Problem Library has worked problems with a step-by-step solver that explains the reasoning rather than printing an answer.
Learn the three log values today, then solve worked example 4 again with [Zn2+] = 0.1 M; you should get about 1.13 V.
