Important Chemistry Formulas For NEET 2027 Exam- Topic-wise Formulas PDF

NEET 2027 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 2027, short explanations, and smart tips that make last-minute learning smoother.

NEET 2027 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:
$E = h\nu = \frac{hc}{\lambda}$
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:
$h\nu = h\nu_0 + \frac{1}{2}mv_{\max}^2$
Bohr’s Quantisation of Angular Momentum states that the angular momentum of an electron is quantised in integral multiples of $\frac

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:

`$l = 0, 1, 2, \ldots, n-1$`

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

`$m_l = -l, -(l-1), \ldots, 0, \ldots, +(l-1), +l$`

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

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

Thermodynamics: Most Useful Formulas

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

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

`$\Delta U = q + w$`

Work Done During Isothermal Expansion of an ideal gas:

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

Work Done in an Adiabatic Process can be expressed in two ways:

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

or

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

Difference Between Heat Capacities at constant pressure and constant volume:

`$C_p - C_v = R$`

The ratio of heat capacities is:

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

Enthalpy Change is related to internal energy and the change in moles of gaseous substances:

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

Gibbs Free Energy Change indicates spontaneity and is linked to enthalpy and entropy:

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

The relationship between standard Gibbs free energy change and the equilibrium constant is:

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

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
$\text{Rate} = -\frac{d[R]}{dt} = \frac{d[P]}{dt}$
Integrated Rate Law for a First-Order Reaction
$k = \frac{2.303}{t}\log\left(\frac{[R]_0}{[R]_t}\right)$
Half-Life of a First-Order Reaction
$t_{1/2} = \frac{0.693}{k}$
The half-life of a first-order reaction is independent of the initial concentration.
Units of Rate Constant
- First order: $s^{-1}$
- Second order: $\text{L mol}^{-1}\text{s}^{-1}$
Arrhenius Equation
$k = A e^{-\frac{E_a}{RT}}$
or
$\ln k = \ln A - \frac{E_a}{RT}$

Chemical Equilibrium: Quick Recall Formulas

Equilibrium Constant
$K_c = \frac{[C]^c[D]^d}{[A]^a[B]^b}$
For a reaction $aA + bB \rightleftharpoons cC + dD$, where the concentrations are expressed in mol/L.
Relation Between $K_p$ and $K_c$
$K_p = K_c(RT)^{\Delta n}$
where $\Delta n = (c+d)-(a+b)$, considering only gaseous products and reactants.
Reaction Quotient
$Q_c = \frac{[C]^c[D]^d}{[A]^a[B]^b}$
Here, $Q_c$ uses the concentrations at any given moment, while $K_c$ uses the equilibrium concentrations.

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:

pH of a Solution
$\mathrm{pH} = -\log [\mathrm{H}^+]$
pOH of a Solution
$\mathrm{pOH} = -\log [\mathrm{OH}^-]$
Relationship Between pH and pOH
$\mathrm{pH} + \mathrm{pOH} = 14$
Relationship Between $K_a$ and $K_b$
The acid dissociation constant $K_a$ and base dissociation constant $K_b$ are related through the ionic product of water:
$K_w = K_a \times K_b$
$25^\circ\mathrm{C}$
$\mathrm{p}K_a + \mathrm{p}K_b = 14$
Ostwald’s Dilution Law
For weak electrolytes, the degree of dissociation $(\alpha)$ is related to $K_a$ and concentration $(C)$:
$\alpha = \sqrt{\frac{K_a}{C}}$
The exact relationship is:
$K_a = \frac{C\alpha^2}{1-\alpha}$
Henderson–Hasselbalch Equation
For acidic buffer solutions, pH is expressed in terms of salt and acid concentrations:
$\mathrm{pH} = \mathrm{p}K_a + \log\left(\frac{[\mathrm{Salt}]}{[\mathrm{Acid}]}\right)$

Solutions & Colligative Properties: Formulas for NEET 2027

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

Mole Fraction
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
Molality is the number of moles of solute per kilogram of solvent:
$m = \frac{\text{Moles of solute}}{\text{Mass of solvent (kg)}}$
Molarity
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
Gas pressure is proportional to its mole fraction in the solution:
$p = K_H x$
Raoult’s Law
The vapour pressure of a solvent is proportional to its mole fraction:
$P_A = x_A P_A^0$
Relative Lowering of Vapour Pressure
For a solution containing a non-volatile solute:
$\frac{P_A^0-P_A}{P_A^0} = x_B$
Elevation in Boiling Point
$\Delta T_b = K_b m$
Depression in Freezing Point
$\Delta T_f = K_f m$
Osmotic Pressure
$\pi = CRT$
van’t Hoff Factor
The van’t Hoff factor accounts for the association or dissociation of solute particles:
$i = \frac{\text{Observed colligative property}}{\text{Calculated colligative property}}$

Electrochemistry: NEET 2027 Formulas

Faraday’s First Law of Electrolysis relates the mass of a substance deposited to the current and time:
$W = ZIt$
Alternatively,
$W = \frac{EIt}{96500}$
Equivalent Mass
The equivalent mass is calculated using molar mass and the $n$-factor:
$\text{Equivalent mass} = \frac{\text{Molar mass}}{n\text{-factor}}$
Relationship Between Standard Gibbs Energy and Cell Potential
$\Delta G^\circ = -nFE_{\text{cell}}^\circ$
Relationship Between Standard Cell Potential and Equilibrium Constant (at 298 K)
$\log K = \frac{nE_{\text{cell}}^\circ}{0.0591}$
or
$E_{\text{cell}}^\circ = \frac{0.0591}{n}\log K$
Nernst Equation
The Nernst equation gives the cell potential under non-standard conditions (298 K):
$E_{\text{cell}} = E_{\text{cell}}^\circ - \frac{0.0591}{n}\log Q$
where the reaction quotient is
$Q = \frac{a_C^c a_D^d}{a_A^a a_B^b}$
for the reaction $aA + bB \rightleftharpoons cC + dD$.
Here, $a_A$, $a_B$, $a_C$, and $a_D$ represent the activities of the respective species, while $a$, $b$, $c$, and $d$ are their stoichiometric coefficients. For dilute solutions, activities may be approximated by concentrations when appropriate. Pure solids and liquids are omitted from the reaction quotient.

NEET 2027 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 composition/atomic mass

Important Named Reactions

Aldol Condensation
$\text{Aldehyde/Ketone} \xrightarrow{\text{dil. base}} \beta\text{-hydroxy aldehyde/ketone} \xrightarrow{\Delta} \alpha,\beta\text{-unsaturated carbonyl compound}$
Cannizzaro Reaction
Aldehydes without an $\alpha$-hydrogen undergo disproportionation in the presence of a concentrated base. One molecule is oxidised to a carboxylate salt, while the other is reduced to an alcohol.
$2\mathrm{RCHO} + \mathrm{NaOH} \rightarrow \mathrm{RCOONa} + \mathrm{RCH_2OH}$
Wurtz Reaction
$2\mathrm{R-X} + 2\mathrm{Na} \xrightarrow{\text{dry ether}} \mathrm{R-R} + 2\mathrm{NaX}$
Coupling of alkyl halides using sodium metal in dry ether.
Sandmeyer Reaction
$\mathrm{ArN_2^+X^-} \xrightarrow{\mathrm{CuX}} \mathrm{ArX} + \mathrm{N_2}\uparrow$
An aromatic diazonium salt is converted into an aryl halide using a cuprous halide.
Kolbe’s Electrolysis
$2\mathrm{RCOO^-} \rightarrow \mathrm{R-R} + 2\mathrm{CO_2} + 2e^-$
Decarboxylation and coupling of carboxylate ions during electrolysis produce an alkane.

How to Revise Chemistry Formulas for NEET 2027?

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.

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.

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.

Focus on Weak Areas First in NEET Chemistry Revision

• We all have those tricky formulas that just won’t stay in our heads.

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

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.

NEET 2027 Inorganic Chemistry Quick Revision

Inorganic Chemistry requires fewer equations and is more reliant on facts from NCERT textbooks, periodic trends, reactions, properties, and exceptions. Thus, rather than including redundant equations, students should focus on revising:

• Periodic trends and key exceptions
• Oxidation states
• Chemical bonding and geometry
• Coordination compounds and nomenclature
• Coordination number and oxidation state
• d- and f- Block elements
• Key reactions and compounds as per the syllabus

Based on the recent analysis of the NEET Chemistry paper of 2026 by Careers360, it was found that topics like Coordination Compounds, Hydrocarbons, d- and f-Block Elements, Chemical Bonding, and Thermodynamics are most important; however, chapter-wise trends should not be considered predictions for NEET 2027.

Common Mistakes While Revising NEET Chemistry Formulas

By avoiding common mistakes in the revision of NEET Chemistry formulas, a student will be able to recall formulas better, make fewer calculation mistakes, and use the equation correctly for answering numerical problems.

• Memorising formulas without understanding their variables
• Forgetting units and conditions of application
• Confusing similar formulas from different chapters
• Using formulas without checking whether the reaction or process satisfies the required conditions
• Ignoring the role of the van't Hoff factor
• Forgetting stoichiometric coefficients while writing equilibrium expressions
• Using the wrong sign convention in thermodynamics
• Memorising Organic Chemistry reactions without learning reagents and products
• Treating Inorganic Chemistry as formula-based instead of revising NCERT