Physical Chemistry Formula Sheet for NEET 2026 Exam - Check Here

Physical Chemistry Formula Sheet for NEET 2026 — Chapter-wise Complete List

Scoring well in Physical Chemistry starts with having the right resources ready. This physical chemistry formula sheet covers every chapter from the latest NEET 2026 syllabus organized for last-minute revision.

Chapter 1 · Some Basic Concepts of Chemistry

Mole Concept:

• Number of moles: $n = W / M$

• Number of particles: $N = n \times N_A$

• Molar volume at STP: $V = n \times 22.4 \text{ L}$

• Mole fraction: $\chi_A = n_A / (n_A + n_B)$

• Mole fraction (sum): $\chi_A + \chi_B = 1$

Concentration Terms:

• Molarity: $M = \text{moles of solute} / \text{L of solution}$

• Molality: $m = \text{moles of solute} / \text{kg of solvent}$

• Normality: $N = \text{equivalents of solute} / \text{L of solution}$

• Relation between M and N: $N = M \times n\text{-factor}$

• % by mass: $% w/w = (W_{solute} / W_{solution}) \times 100$

• % by volume: $% v/v = (V_{solute} / V_{solution}) \times 100$

• ppm: $\text{ppm} = (W_{solute} / W_{solution}) \times 10^6$

Stoichiometry

• Empirical formula factor: $n = \text{molecular formula mass} / \text{empirical formula mass}$

• Limiting reagent yield: $\text{theoretical yield} = \text{moles of LR} \times \text{stoichiometric ratio} \times M$

• % yield: $% \text{ yield} = (\text{actual yield} / \text{theoretical yield}) \times 100$

• % purity: $% \text{ purity} = (\text{pure mass} / \text{total mass}) \times 100$

Equivalent Concept:

• Equivalents: $\text{eq} = W / E$

• Equivalent weight (acid): $E = M / \text{basicity}$

• Equivalent weight (base): $E = M / \text{acidity}$

• Equivalent weight (oxidant/reductant): $E = M / n\text{-factor}$

• Normality equation: $N_1 V_1 = N_2 V_2$

• Molarity equation: $M_1 V_1 = M_2 V_2$

Chapter 2 · Structure of Atom

Electromagnetic Radiation:

• Wave relation: $c = \nu \lambda$

• Energy of photon: $E = h\nu = hc/\lambda$

• Wave number: $\bar{\nu} = 1/\lambda$

Bohr's Model:

• Radius of nth orbit: $r_n = 0.529 \times n^2 / Z \text{ Å}$

• Velocity of electron in nth orbit: $v_n = 2.18 \times 10^6 \times Z/n \text{ m/s}$

• Energy of nth orbit: $E_n = -13.6 \times Z^2/n^2 \text{ eV}$

• Energy of nth orbit (J): $E_n = -2.18 \times 10^{-18} \times Z^2/n^2 \text{ J}$

• Energy of emitted photon: $\Delta E = E_{n_2} - E_{n_1} = h\nu$

• Frequency of emitted radiation: $\nu = (E_{n_2} - E_{n_1}) / h$

Rydberg Equation

• Rydberg formula: $1/\lambda = R_H (1/n_1^2 - 1/n_2^2)$

• Rydberg constant: $R_H = 1.097 \times 10^7 \text{ m}^{-1}$

• For hydrogen series: $\bar{\nu} = R_H \times Z^2 (1/n_1^2 - 1/n_2^2)$

Quantum Mechanics

• de Broglie wavelength: $\lambda = h/mv = h/p$

• de Broglie (for electron accelerated through V volts): $\lambda = h/\sqrt{2meV}$

• Heisenberg uncertainty principle: $\Delta x \cdot \Delta p \geq h/4\pi$

• Heisenberg (energy–time form): $\Delta E \cdot \Delta t \geq h/4\pi$

Quantum Numbers

• Max electrons in shell n: $2n^2$

• Max electrons in subshell: $2(2l+1)$

• Number of orbitals in subshell: $(2l+1)$

• Number of subshells in nth shell: $n$

• Number of orbitals in nth shell: $n^2$

Chapter 3 · Classification of Elements & Periodicity

(No mathematical formulas; concept-based chapter. Key trends below.)

• Atomic radius trend (period): $\text{decreases} \rightarrow$

• Atomic radius trend (group): $\text{increases} \downarrow$

• Ionisation enthalpy trend (period): $\text{increases} \rightarrow$

• Electronegativity trend (period): $\text{increases} \rightarrow$

• Effective nuclear charge: $Z_{eff} = Z - \sigma$ (Slater's rules)

Chapter 4 · Chemical Bonding & Molecular Structure

Formal Charge

• Formal charge: $FC = V - N - B/2$

• where V = valence electrons, N = non-bonding electrons, B = bonding electrons

Bond Parameters

• Bond order: $BO = (\text{bonding electrons} - \text{antibonding electrons}) / 2$

• Relation: higher bond order → shorter bond length → higher bond energy

Dipole Moment

• Dipole moment: $\mu = q \times d$

• Unit: $1 \text{ D} = 3.336 \times 10^{-30} \text{ C·m}$

Chapter 5 · States of Matter

Gas Laws

• Boyle's law: $P_1 V_1 = P_2 V_2$

• Charles's law: $V_1/T_1 = V_2/T_2$

• Gay-Lussac's law: $P_1/T_1 = P_2/T_2$

• Avogadro's law: $V_1/n_1 = V_2/n_2$

• Combined gas law: $P_1 V_1/T_1 = P_2 V_2/T_2$

• Ideal gas equation: $PV = nRT$

• Density form: $PM = dRT$

• Dalton's law: $P_{total} = P_1 + P_2 + P_3 \ldots$

• Partial pressure: $P_i = \chi_i \times P_{total}$

Kinetic Theory of Gases

• RMS speed: $u_{rms} = \sqrt{3RT/M}$

• Average speed: $u_{avg} = \sqrt{8RT/\pi M}$

• Most probable speed: $u_{mp} = \sqrt{2RT/M}$

• Speed ratio: $u_{mp} : u_{avg} : u_{rms} = 1 : 1.128 : 1.224$

• Average KE per mole: $KE = (3/2)RT$

• Average KE per molecule: $KE = (3/2)k_BT$

• Graham's law: $r_1/r_2 = \sqrt{M_2/M_1} = \sqrt{d_2/d_1}$

Real Gases

• van der Waals equation: $(P + an^2/V^2)(V - nb) = nRT$

• Compressibility factor: $Z = PV/nRT$

• For ideal gas: $Z = 1$

• Boyle temperature: $T_B = a/Rb$

• Critical temperature: $T_c = 8a/27Rb$

• Critical pressure: $P_c = a/27b^2$

• Critical volume: $V_c = 3b$

Chapter 6 · Thermodynamics

Basic Relations

• First law: $\Delta U = q + w$

• Work at constant pressure: $w = -P_{ext} \Delta V$

• Work in reversible isothermal: $w = -2.303 nRT \log(V_2/V_1)$

• Enthalpy: $H = U + PV$

• At constant pressure: $\Delta H = q_p$

• At constant volume: $\Delta U = q_v$

• Relation: $\Delta H = \Delta U + \Delta n_g RT$

Thermochemistry

• Hess's law: $\Delta H_{rxn} = \Sigma \Delta H_f(\text{products}) - \Sigma \Delta H_f(\text{reactants})$

• From bond enthalpies: $\Delta H = \Sigma \text{ BE(reactants)} - \Sigma \text{ BE(products)}$

• Kirchhoff's equation: $\Delta H_{T_2} = \Delta H_{T_1} + \Delta C_p (T_2 - T_1)$

Entropy & Gibbs Energy

• Entropy change: $\Delta S = q_{rev}/T$

• Second law: $\Delta S_{universe} = \Delta S_{sys} + \Delta S_{surr} > 0$

• Gibbs free energy: $\Delta G = \Delta H - T\Delta S$

• Standard Gibbs energy: $\Delta G° = \Delta H° - T\Delta S°$

• Spontaneity: $\Delta G < 0 \rightarrow \text{spontaneous}$

• At equilibrium: $\Delta G = 0$

• Relation with K: $\Delta G° = -RT \ln K$

• Relation with K (log form): $\Delta G° = -2.303 RT \log K$

Heat Capacity

• Heat at constant pressure: $q_p = nC_p \Delta T$

• Heat at constant volume: $q_v = nC_v \Delta T$

• For ideal gas: $C_p - C_v = R$

• Ratio: $\gamma = C_p/C_v$

Chapter 7 · Equilibrium

Chemical Equilibrium

• Equilibrium constant: $K_c = [C]^c[D]^d / [A]^a[B]^b$

• Kp from Kc: $K_p = K_c(RT)^{\Delta n_g}$

• Reaction quotient: $Q_c = [C]^c[D]^d / [A]^a[B]^b$ (at any point)

• If $Q < K_c \rightarrow \text{forward reaction}$

• If $Q > K_c \rightarrow \text{backward reaction}$

• If $Q = K_c \rightarrow \text{at equilibrium}$

• van't Hoff equation: $\log(K_2/K_1) = \Delta H°/2.303R \times (1/T_1 - 1/T_2)$

• Relation with Gibbs: $\Delta G° = -RT \ln K_c$

Degree of Dissociation

• General: $\alpha = \text{moles dissociated} / \text{initial moles}$

• For $AB \rightleftharpoons A + B$: $K_c = C\alpha^2 / (1-\alpha)$

• When $\alpha \ll 1$: $K_c \approx C\alpha^2$, so $\alpha = \sqrt{K_c/C}$

Ionic Equilibrium

• pH: $pH = -\log[H^+]$

• pOH: $pOH = -\log[OH^-]$

• Relation: $pH + pOH = 14 \text{ (at 25°C)}$

• Kw: $K_w = [H^+][OH^-] = 10^{-14} \text{ at 25°C}$

• pKw: $pK_w = pH + pOH = 14$

• Ka: $K_a = [H^+][A^-]/[HA]$

• Kb: $K_b = [BH^+][OH^-]/[B]$

• Relation: $K_a \times K_b = K_w$

• pKa + pKb: $pK_a + pK_b = pK_w = 14$

• pH of weak acid: $[H^+] = \sqrt{K_a \times C}$

• pH of weak base: $[OH^-] = \sqrt{K_b \times C}$

• Degree of dissociation (weak acid): $\alpha = \sqrt{K_a/C}$

• Henderson-Hasselbalch (acid buffer): $pH = pK_a + \log([A^-]/[HA])$

• Henderson-Hasselbalch (base buffer): $pOH = pK_b + \log([BH^+]/[B])$

• Solubility product: $K_{sp} = [M^{n+}]^a[X^{m-}]^b$

• For $AB \rightleftharpoons A^+ + B^-$: $K_{sp} = s^2$

• For $AB_2 \rightleftharpoons A^{2+} + 2B^-$: $K_{sp} = 4s^3$

• For $A_2B_3 \rightleftharpoons 2A^{3+} + 3B^{2-}$: $K_{sp} = 108s^5$

• Ionic product vs Ksp: $\text{if } Q > K_{sp} \rightarrow \text{precipitation occurs}$

Chapter 8 · Redox Reactions

• Oxidation number rule (neutral compound): $\Sigma \text{ oxidation numbers} = 0$

• Oxidation number rule (ion): $\Sigma \text{ oxidation numbers} = \text{charge on ion}$

• n-factor (acid/base): $n = \text{basicity or acidity}$

• n-factor (redox): $n = \text{change in oxidation number per formula unit}$

• Equivalents: $\text{meq} = M \times n\text{-factor} \times V(\text{L}) \times 1000$

• Equivalents balance: $\text{meq of oxidant} = \text{meq of reductant}$

Chapter 9 · Solutions

Concentration

• Molarity: $M = n_{solute} / V_{solution}(\text{L})$

• Molality: $m = n_{solute} / W_{solvent}(\text{kg})$

• Mole fraction: $\chi_A = n_A / (n_A + n_B)$

• Mass fraction: $w_A = W_A / (W_A + W_B)$

• Relation M and m: $m = (M \times 1000) / (1000d - M \times M_2)$

Raoult's Law & VP

• Raoult's law: $P_A = \chi_A \times P°_A$

• Total pressure (ideal): $P_{total} = \chi_A P°_A + \chi_B P°_B$

• Relative lowering of VP: $(P°_A - P_A)/P°_A = \chi_B$

• Relative lowering of VP: $(P°_A - P_A)/P°_A = n_B/(n_A + n_B)$

Colligative Properties

• Elevation of boiling point: $\Delta T_b = K_b \times m$

• Depression of freezing point: $\Delta T_f = K_f \times m$

• Molar mass from $\Delta T_b$: $M_2 = (K_b \times W_2 \times 1000) / (\Delta T_b \times W_1)$

• Molar mass from $\Delta T_f$: $M_2 = (K_f \times W_2 \times 1000) / (\Delta T_f \times W_1)$

• Osmotic pressure: $\pi = MRT$

• Osmotic pressure (Van't Hoff): $\pi V = n_B RT$

• Molar mass from osmosis: $M_2 = W_2 RT / \pi V$

• Van't Hoff factor: $i = \text{observed colligative property} / \text{calculated colligative property}$

• i for dissociation: $i = 1 + (n-1)\alpha$

• i for association: $i = 1 - (1 - 1/n)\alpha$

• Modified $\Delta T_b$: $\Delta T_b = i \times K_b \times m$

• Modified $\Delta T_f$: $\Delta T_f = i \times K_f \times m$

• Modified $\pi$: $\pi = i \times MRT$

• Degree of dissociation from i: $\alpha = (i-1)/(n-1)$

Henry's Law

• Henry's law: $p = K_H \times \chi$

• Higher $K_H$ → lower solubility of gas

Chapter 10 · Electrochemistry

Electrolytic Conduction

• Resistance: $R = \rho \times l/A$

• Conductance: $G = 1/R$

• Conductivity: $\kappa = 1/\rho = G \times l/A$

• Cell constant: $G^* = l/A$

• Molar conductivity: $\Lambda_m = \kappa \times 1000/M$

• Molar conductivity (SI): $\Lambda_m = \kappa/C$

• Kohlrausch's law: $\Lambda°m = \Sigma \lambda°{ions}$

• Degree of dissociation: $\alpha = \Lambda_m/\Lambda°_m$

• Ka from conductance: $K_a = C\alpha^2/(1-\alpha)$

Electrochemical Cells

• Cell EMF: $E°{cell} = E°{cathode} - E°_{anode}$

• Gibbs and EMF: $\Delta G° = -nFE°_{cell}$

• K and EMF: $\Delta G° = -RT \ln K = -nFE°$

• K from EMF: $\log K = nE°/0.0591 \text{ (at 25°C)}$

Nernst Equation

• Nernst equation: $E_{cell} = E°_{cell} - (RT/nF) \ln Q$

• Nernst at 25°C: $E_{cell} = E°_{cell} - (0.0591/n) \log Q$

• At equilibrium: $E_{cell} = 0$ and $Q = K$

Faraday's Laws

• First law: $W = ZIt$

• Electrochemical equivalent: $Z = M/(n \times F)$

• Charge: $Q = It$

• Moles deposited: $\text{moles} = It/(n \times F)$

• Second law: $W_1/W_2 = E_1/E_2$

Chapter 11 · Chemical Kinetics

Rate of Reaction

• Rate (general): $r = -\frac{1}{a} d[A]/dt = -\frac{1}{b} d[B]/dt = \frac{1}{c} d[C]/dt$

• Rate law: $\text{rate} = k[A]^m[B]^n$

• Overall order: $= m + n$

• Units of k (nth order): $k = (\text{mol/L})^{1-n} \text{ s}^{-1}$

Integrated Rate Laws

• Zero order: $[A]_t = [A]_0 - kt$

• Zero order half-life: $t_{1/2} = [A]_0/2k$

• Zero order units of k: $\text{mol L}^{-1} \text{s}^{-1}$

• First order: $\ln[A]_t = \ln[A]_0 - kt$

• First order (log form): $\log[A]_t = \log[A]_0 - kt/2.303$

• First order k: $k = (2.303/t)\log([A]_0/[A]_t)$

• First order half-life: $t_{1/2} = 0.693/k$

• First order units of k: $\text{s}^{-1}$

• Second order: $1/[A]_t = 1/[A]_0 + kt$

• Second order half-life: $t_{1/2} = 1/(k[A]_0)$

• Second order units of k: $\text{L mol}^{-1} \text{s}^{-1}$

Temperature Dependence

• Arrhenius equation: $k = Ae^{-E_a/RT}$

• Arrhenius (log form): $\log k = \log A - E_a/(2.303RT)$

• Two-temperature form: $\log(k_2/k_1) = E_a/2.303R \times (1/T_1 - 1/T_2)$

• Thumb rule: rate doubles for every 10°C rise

• Temperature coefficient: $\mu = k_{T+10}/k_T \approx 2$

• Activation energy from graph: $E_a = -2.303R \times \text{slope of } \log k \text{ vs } 1/T$

Chapter 12 · Surface Chemistry

Adsorption

• Freundlich adsorption isotherm: $x/m = kP^{1/n}$

• Freundlich (log form): $\log(x/m) = \log k + (1/n)\log P$

• At low P: $x/m \propto P$ (n = 1)

• At high P: $x/m = \text{constant}$ (independent of P)

Langmuir Adsorption

• Langmuir isotherm: $x/m = aP/(1 + bP)$

• At low P: $x/m \propto P$

• At high P: $x/m = a/b$ (monolayer saturation)

Chapter 13 · Solid State

Unit Cell

• Density of unit cell: $d = (Z \times M)/(N_A \times a^3)$

• Edge length from density: $a = (Z \times M/(N_A \times d))^{1/3}$

Packing Efficiency

• Simple cubic (SC): $\text{PE} = 52.4%$, $Z = 1$, $r = a/2$

• Body-centred cubic (BCC): $\text{PE} = 68%$, $Z = 2$, $r = a\sqrt{3}/4$

• Face-centred cubic (FCC/CCP): $\text{PE} = 74%$, $Z = 4$, $r = a\sqrt{2}/4$

• Hexagonal close packing (HCP): $\text{PE} = 74%$, $Z = 6$

Radius Ratio Rules

• Linear (2-coord): $r^+/r^- < 0.155$

• Triangular (3-coord): $r^+/r^- = 0.155 – 0.225$

• Tetrahedral (4-coord): $r^+/r^- = 0.225 – 0.414$

• Octahedral (6-coord): $r^+/r^- = 0.414 – 0.732$

• Cubic (8-coord): $r^+/r^- = 0.732 – 1.000$

Defects

• Schottky defect: cation and anion vacancies equal → density decreases

• Frenkel defect: ion displaced to interstitial site → density unchanged

• Electrical conductivity from defects: $\sigma \propto e^{-E_g/2k_BT}$

Chapter 14 · Nuclear Chemistry

Radioactive Decay

• Decay law: $N = N_0 e^{-\lambda t}$

• Decay law (log form): $\ln(N_0/N) = \lambda t$

• Activity: $A = \lambda N$

• Decay constant and half-life: $\lambda = 0.693/t_{1/2}$

• Half-life: $t_{1/2} = 0.693/\lambda$

• Number of half-lives: $n = t/t_{1/2}$

• Amount remaining: $N = N_0 \times (1/2)^n$

• Average life: $\tau = 1/\lambda = t_{1/2}/0.693$

• Activity units: $1 \text{ Curie} = 3.7 \times 10^{10} \text{ disintegrations/s}$

Nuclear Reactions

• Mass defect: $\Delta m = [Zm_p + (A-Z)m_n] - m_{nucleus}$

• Binding energy: $BE = \Delta m \times c^2$

• Binding energy (MeV): $BE = \Delta m \times 931.5 \text{ MeV}$

• Binding energy per nucleon: $BE/A$

How to Use This Physical Chemistry Formula Sheet Effectively for NEET 2026

Just reading formulas won't improve your score. The real benefit comes from knowing how you apply them during revision and practice sessions.

• Start with the chapters where you feel weakest

• Do not try to memorise everything in one sitting

• Combine the formulas with real question practice using mock tests and PYQs.