Important Chemistry Formulas For NEET 2026 Exam- Topic-wise Formulas PDF

NEET 2026 Chemistry Formula Sheet PDF Download

Chemistry can feel like a memory test sometimes, but with the right direction, it doesn’t have to. Most questions of Chemistry in NEET are formula-based, mainly in Physical Chemistry, and being able to recall the right equation at the right time makes all the difference. Whether you're attempting NEET Chemistry previous years' questions, revising a few hours before your test, solving a mock, or flipping through notes on the go, this is the kind of list that helps you stay focused and score better.

Aspirants can download the NEET Chemistry formula PDF to cover the NEET Chemistry syllabus from here. This formula sheet PDF is designed for quick and clear revision. No extra theory, no unnecessary details, just what is needed to solve MCQs accurately and with confidence. Each section includes important formulas of NEET Chemistry 2026, short explanations, and smart tips that make last-minute learning smoother.

NEET 2026 Physical Chemistry Formula

NEET Physical Chemistry is an important part of the syllabus. Knowing key formulas helps in solving problems quickly and accurately. These formulas cover topics like atomic structure, thermodynamics, and chemical equilibrium.

Atomic Structure

The atomic structure often forms the foundation for many conceptual questions. These formulas help relate energy, wavelength, and the motion of electrons in atoms.

Planck's Quantum Equation relates the energy of a photon to its frequency or wavelength:

$E = \frac{hc}{\lambda} = h\nu$

de Broglie’s Equation gives the relation between wavelength and momentum for any moving particle:

$\lambda = \frac{h}{mv}$

Einstein's Photoelectric Equation explains how light energy is used to eject electrons:

$h\nu = h\nu_0 + \frac{1}{2}mv^2$

Bohr’s Quantisation of Angular Momentum states that the angular momentum of an electron is quantised in integral multiples of $\frac{h}{2\pi}$:

$mvr = \frac{nh}{2\pi}$

Bohr’s Formula for the Radius of the $n^{\text{th}}$ orbit (valid for hydrogen-like atoms):

$r_n = 0.529\,\frac{n^2}{Z}\,\text{\AA}$

Energy of Electron in the $n^{\text{th}}$ orbit (more negative means more tightly bound):

$E_n = -13.6\,\frac{Z^2}{n^2}\,\text{eV}$

Speed of an Electron in the $n^{\text{th}}$ orbit of a hydrogen-like atom:

$v = 2.18 \times 10^6 \,\frac{Z}{n}\,\text{m/s}$

Heisenberg Uncertainty Principle

The Heisenberg Uncertainty Principle states that we cannot precisely know both the position and the momentum of a particle at the same time:

Heisenberg's Uncertainty Principle:

$\Delta x \cdot \Delta p \geq \frac{h}{4\pi}$

If momentum is expressed as $p = mv$, the uncertainty relation becomes:

$\Delta x \cdot \Delta v \geq \frac{h}{4\pi m}$

Quantum Numbers

Each electron in an atom is described by a unique set of four quantum numbers:

Principal quantum number $(n)$ defines the main energy level or shell:

$n = 1, 2, 3, \ldots$

Azimuthal quantum number $(l)$ defines the subshell or shape of the orbital:

$l = 0 \text{ to } n-1$

Magnetic quantum number $(m)$ defines the orientation of the orbital in space:

$m = -l \text{ to } +l$

Spin quantum number $(s)$ defines the spin of the electron:

$s = +\frac{1}{2} \text{ or } -\frac{1}{2}$

Thermodynamics: Most Useful Formulas

Thermodynamics is full of concepts, but in NEET, most questions are numerical. So focus on these formulas:

The First Law of Thermodynamics relates internal energy, heat, and work:

$\Delta U = q + w$

Work done during isothermal expansion (ideal gas) is given by:

$w = -nRT \ln\left(\frac{V_2}{V_1}\right)$

Work done in an adiabatic process can be expressed in two ways:

$w = \frac{P_1V_1 - P_2V_2}{\gamma - 1}$

or

$w = \frac{nR(T_1 - T_2)}{\gamma - 1}$

The difference between heat capacities at constant pressure and volume:

$C_p - C_v = R$

and

$\gamma = \frac{C_p}{C_v}$

Enthalpy change is related to internal energy and the change in moles of gas:

$\Delta H = \Delta U + \Delta n_g RT$

Gibbs free energy change tells the spontaneity and is linked to enthalpy and entropy:

$\Delta G = \Delta H - T\Delta S$

and

$\Delta G^\circ = -RT \ln K$

Chemical Kinetics: Formulas to Save Time

Speed-based questions in NEET are usually direct and formula-driven. Focus on these:

The rate of a chemical reaction is defined as the change in concentration of reactants or products per unit time:

Rate of reaction:

$\text{Rate} = -\frac{d[R]}{dt} = \frac{d[P]}{dt}$

For a first-order reaction, the integrated rate law is:

$k = \frac{2.303}{t}\log\left(\frac{[R]_0}{[R]}\right)$

The half-life of a first-order reaction is independent of concentration:

$t_{1/2} = \frac{0.693}{k}$

Units of rate constant vary with the order of reaction:

First Order: $s^{-1}$

Second Order: $L\,mol^{-1}\,s^{-1}$

Arrhenius equation relates the rate constant to temperature and activation energy:

$k = Ae^{-E_a/RT}$

or

$\ln k = \ln A - \frac{E_a}{RT}$

### Chemical Equilibrium: Quick Recall Formulas

Equilibrium constant:

$K_c = \frac{[\text{Products}]^{\text{coeff}}}{[\text{Reactants}]^{\text{coeff}}}$

Relation between $K_p$ and $K_c$:

$K_p = K_c(RT)^{\Delta n}$

Reaction quotient:

$Q = \frac{[\text{Products}]^{\text{coeff}}}{[\text{Reactants}]^{\text{coeff}}}$

Direction of reaction:

• If Q<K, the forward reaction proceeds.

• If Q>K, the backward reaction proceeds.

• If Q=K, the system is at equilibrium.

Ionic Equilibrium: Strong vs Weak Electrolytes

Important for pH, Ka, and Kb-based questions.

pH and pOH relate to the concentration of hydrogen and hydroxide ions:

$\mathrm{pH} = -\log[H^+]$

$\mathrm{pOH} = -\log[OH^-]$

Also,

$\mathrm{pH} + \mathrm{pOH} = 14$

$K_a$ and $K_b$ are related through the ionic product of water:

$K_w = K_a \cdot K_b$

and

$\mathrm{p}K_a + \mathrm{p}K_b = 14$

Ostwald’s Dilution Law for weak electrolytes relates the degree of dissociation $(\alpha)$ with $K_a$ and concentration:

$\alpha = \sqrt{\frac{K_a}{C}}$

and

$K_a = \frac{C\alpha^2}{1-\alpha}$

Henderson–Hasselbalch equation for buffer solutions gives the pH in terms of salt and acid concentrations:

$\mathrm{pH} = \mathrm{p}K_a + \log\left(\frac{[\text{Salt}]}{[\text{Acid}]}\right)$

Solutions & Colligative Properties: Formulas for NEET 2026

This chapter has many numerical questions. Just knowing which formula to apply makes a huge difference.

The mole fraction of component A is the ratio of its moles to the total moles:

$x_A = \frac{n_A}{n_A + n_B}$

Molality is the number of moles of solute per kg of solvent:

$m = \frac{\text{moles of solute}}{\text{mass of solvent (kg)}}$

Molarity is the number of moles of solute per litre of solution:

$M = \frac{\text{moles of solute}}{\text{volume of solution (L)}}$

Henry’s Law states that gas pressure is directly proportional to its mole fraction:

$p = K_H \cdot x$

Raoult’s Law says the vapour pressure of a solvent is proportional to its mole fraction:

$P_A = x_A \cdot P_A^0$

Relative lowering of vapour pressure is equal to the mole fraction of solute:

$\frac{\Delta P}{P^0} = x_B$

Elevation in boiling point is directly proportional to molality:

$\Delta T_b = K_b \cdot m$

Depression in freezing point is also directly proportional to molality:

$\Delta T_f = K_f \cdot m$

Osmotic pressure depends on molarity, gas constant, and temperature:

$\pi = CRT$

van’t Hoff factor corrects for dissociation/association in colligative properties:

$i = \frac{\text{Observed colligative property}}{\text{Calculated colligative property}}$

Electrochemistry: NEET 2026 Formulas

Faraday’s First Law of Electrolysis relates the mass of substance deposited to the current and time:

$W = ZIt$

or

$W = \frac{E \cdot I \cdot t}{96500}$

The number of equivalents is calculated using molar mass and n-factor:

$\text{Equivalent} = \frac{\text{Molar Mass}}{\text{n-factor}}$

The relation between the standard Gibbs energy and cell potential is:

$\Delta G^\circ = -nFE^\circ$

Also, the standard cell potential is related to the equilibrium constant:

$E^\circ_{\text{cell}} = \frac{0.0591}{n}\log K$

The Nernst Equation gives the cell potential under non-standard conditions:

$E_{\text{cell}} = E^\circ_{\text{cell}} - \frac{0.0591}{n}\log\left(\frac{[\text{Products}]}{[\text{Reactants}]}\right)$

NEET 2026 Organic Chemistry Formula

NEET Organic Chemistry deals with the structure, properties, and reactions of carbon compounds. Remembering key reactions and mechanisms is important for solving NEET questions. This section provides important formulas, reaction types, and patterns to help you revise quickly and accurately.

Organic Chemistry: Reaction Mechanisms & Named Reactions

This topic is all about pattern recognition in the NEET exam.
But still, here are some quick equations and key reactions:

General Formulas

IUPAC Naming Priority Order:
Carboxylic acid > Anhydride > Ester > Acid halide > Amide > Nitrile > Aldehyde > Ketone > Alcohol > Amine > Alkene > Alkyne > Alkane > Ether > Halide

Empirical formula:
Empirical formula=Percentage compositionAtomic mass

Important Named Reactions

Aldol Condensation:

$\text{Aldehyde/Ketone} + \text{Base} \rightarrow \beta\text{-hydroxy aldehyde/ketone} \rightarrow \alpha,\beta\text{-unsaturated carbonyl compound}$

Cannizzaro Reaction:

Aldehydes without $\alpha$-hydrogen undergo disproportionation, where one molecule is oxidised to a carboxylic acid and the other is reduced to an alcohol.

Wurtz Reaction:

$2R-X + 2Na \rightarrow R-R + 2NaX$

(Coupling of alkyl halides using sodium metal in dry ether)

Sandmeyer Reaction:

$ArN_2^+X^- + CuX \rightarrow ArX + N_2$

Kolbe’s Electrolysis:

$2RCOO^- \rightarrow R-R + 2CO_2 + 2e^-$

(Decarboxylation and dimerisation of carboxylic acid salts during electrolysis)

Download these PDFs for more details:

How to Revise Chemistry Formulas for NEET 2026?

Having a topic-wise Chemistry formula sheet is quite helpful for NEET preparation, but its effect depends on how it is used. The real question is “how to revise NEET Chemistry formula when time is limited?” Here are a few quick, practical strategies that actually work, especially in the last few weeks or days before the exam.

1. Memorise NEET Chemistry Formulas by Saying and Writing

Don’t just read the formulas silently. Instead, say them out loud and write them down from memory. This makes your brain actively engage with the information, which improves retention. The more senses you involve, the better you remember.

2. Revise Chemistry Topic-Wise in Small Sessions

Don’t try to do the entire Chemistry syllabus in one go. Break your revision into smaller chunks: For example

1. Day 1: Atomic Structure + Thermodynamics

2. Day 2: Kinetics + Equilibrium

3. Day 3: Solutions + Electrochemistry

Each session should last 30–45 minutes max. Shorter, focused sessions are more effective than long, tiring marathons.

3. Focus on Weak Areas First in NEET Chemistry Revision

• We all have those tricky formulas that just won’t stay in our heads—maybe it’s

• Highlight them, bookmark them, and revise them daily. Strengthening weak points gives the best return on your revision time.

4. Use Formula → Question → Formula Technique

A simple but powerful method:

1. Read a formula

2. Solve a question based on it

3. Then recite the formula again

This helps connect the concept to actual problem-solving, which is exactly what the NEET tests.

5. Do a Flash Revision of NEET Chemistry Formulas in the Last Week

In the final 5 to 6 days before the exam, don’t try to learn anything new. Just keep flipping through your formula sheet quickly, like you would with flashcards. This keeps the formulas fresh and helps avoid silly mistakes.

Bonus Tip: Use the Sheet as a Night-Before Cheat Code

The night before the exam, take 20 minutes to go through the whole sheet one last time, not to learn, but just for a quick revision.