JEE Main 2027 Chemistry: Top 50 Formulas for Quick Revision

JEE Main 2027 Chemistry Top 50 Formulas

While studying chemistry, candidates need to revise and practise the chemical equations and symbols. Chemistry is a tough subject, but when candidates practise chemical equations and review the properties, formulas, and symbols, they will have command over the subject. Candidates can check the JEE Main Chemistry formulas below.

JEE Main Formulas of Physical Chemistry

Some Basic Concepts in Chemistry

1. Boyle's Law: $P_1 V_1=P_2 V_2$ (at constant T and n )

2. Charles's Law: $\frac{V_1}{T_1}=\frac{V_2}{T_2}($ at constant P and n$)$

3. Avogadro's Law: $\frac{V}{n}=$ constant

4. Average Atomic Mass: $=\frac{\Sigma(\text { Mass of Isotopes })_i \times(\% \text { abundance })_i}{100}$

5. Mole: $=\frac{\mathrm{W}}{\mathrm{M}}=\frac{(\mathrm{Wt} . \text { of substance in gm. })}{(\text { Molar mass of substance }(\mathrm{G} . \mathrm{m} . \mathrm{m}))}$

6. Mass $\%$ of an element $=\frac{\text { Mass of that element in one mole of the compound }}{\text { Molar mass of the compound }} \times 100$

7. Equivalent Weight $=\frac{\text { Molecular weight }}{\mathrm{n}-\text { factor }(\mathrm{x})}$

Atomic Structure

Frequency $\nu=\frac{1}{\mathrm{~T}}$

Wave number $(\bar{\nu})$ $\bar{\nu}=\frac{1}{\lambda}$

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

Line Spectrum of Hydrogen-like atoms: $\frac{1}{\lambda}=R Z^2\left(\frac{1}{n_1^2}-\frac{1}{n_2^2}\right)$

Bohr radius of nth orbit:

$\mathrm{r}_{\mathrm{n}}=0.529 \frac{\mathrm{n}^2}{\mathrm{Z}} \mathrm{~A}^0$

Velocity of electron in the nth orbit:

$\mathrm{V}_{\mathrm{n}}=\left(2.18 \times 10^6\right) \frac{\mathrm{Z}}{\mathrm{n}} \mathrm{~m} / \mathrm{s}$

where Z is the atomic number

Total energy of an electron in the nth orbit:

$\mathrm{E}_{\mathrm{n}}=-13.6 \frac{\mathrm{Z}^2}{\mathrm{n}^2} \mathrm{eV}=-2.18 \times 10^{-18} \frac{\mathrm{Z}^2}{\mathrm{n}^2} \mathrm{~J}$

where Z is the atomic number

Heisenberg Uncertainty Principle: $\Delta x. \Delta P \geq \frac{h}{4 \pi}$

$\mathrm{E}_{\mathrm{n}}=-\frac{1312 \times \mathrm{Z}^2}{\mathrm{n}^2} \mathrm{~kJ} / \mathrm{mol}$

Chemical Thermodynamics

Expansion Work: $=\mathrm{P} \times \Delta \mathrm{V}=-\mathrm{P}_{\text {ext. }}\left[\mathrm{V}_2-\mathrm{V}_1\right]$

$\mathrm{P}=$ external pressure And $\Delta \mathrm{V}=$ increase or decrease in volume.

Work done in a reversible isothermal process:

$\begin{aligned} & W=-2.303 n R T \log _{10}\left(\frac{V_2}{V_1}\right) \\ & W=-2.303 n R T \log _{10}\left(\frac{P_1}{P_2}\right)\end{aligned}$

Work done in an irreversible isothermal process:

Work $=-\mathrm{P}_{\text {ext. }}\left(\mathrm{V}_2-\mathrm{V}_1\right)$

That is, Work $=-\mathrm{P} \times \Delta \mathrm{V}$

$W=\Delta E=n C_V \Delta T$

Enthalpy: $H=U+p V$

First Law of Thermodynamics: $\Delta U=q+W$

$\Delta \mathrm{G}=\Delta \mathrm{H}-\mathrm{T} \Delta(\mathrm{S})$

$\Delta G=-n F E$

Equilibrium

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

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

Relation between pH and pOH: $\mathrm{pH}+\mathrm{pOH}=14$ (at 25°C)
Henderson-Hasselbalch Equation: $\mathrm{pH}=\mathrm{p} K_{\mathrm{a}}+\log \frac{[\text { Salt }]}{[\text { Acid }]}$

Ionic Product of Water:

$K_{\mathrm{w}}=\left[\mathrm{H}^{+}\right]\left[\mathrm{OH}^{-}\right]=10^{-14}$

Solubility Product:

$K_{\mathrm{sp}}=\left[\mathrm{A}^{+}\right]^a\left[\mathrm{~B}^{-}\right]^b$

For a reaction:

$\mathrm{mA}+\mathrm{nB} \rightleftharpoons \mathrm{pC}+\mathrm{qD}$ $\frac{\mathrm{K}_{\mathrm{f}}}{\mathrm{K}_{\mathrm{b}}}=\frac{[\mathrm{C}]^{\mathrm{p}}[\mathrm{D}]^{\mathrm{q}}}{[\mathrm{A}]^{\mathrm{m}}[\mathrm{B}]^{\mathrm{n}}}=\mathrm{K}_{\mathrm{c}}$

$\mathrm{pH}=-\log _{10}\left[\mathrm{H}^{+}\right]$

$\mathrm{k}_{\mathrm{w}}=\left[\mathrm{H}^{+}\right]\left[\mathrm{OH}^{-}\right]=10^{-14}$

$\mathrm{pH}=\mathrm{pK}_{\mathrm{a}}+\log _{10} \frac{[\text { Salt }]}{\text { Acid }}$

$\mathrm{pOH}=\mathrm{pK}_{\mathrm{b}}+\log _{10} \frac{[\text { Salt }]}{[\text { Base }]}$

Electrochemistry

1. Faraday’s First Law of Electrolysis: $\mathrm{W}=\frac{\text { Eit }}{96500}$
2. Faraday’s Second Law of Electrolysis:

$\begin{aligned}
& \frac{E_1}{E_2}=\frac{M_1}{M_2} \text { or } \frac{W_1}{W_2}=\frac{Z_1}{Z_2} \\
& E_1=\text { equivalent weight } \\
& E_2=\text { equivalent weight }
\end{aligned}$
W or M = mass deposited

3. EMF of an Electrochemical Cell:

$\begin{aligned} & E_{\text {cell }} \text { or } E M F=\left[E_{\text {red }}(\text { cathode })-E_{\text {red }}(\text { anode })\right] \\ & E_{\text {eell }}^{\circ} \text { or } E M F^{\circ} \\ & =\left[E_{\text {red }}^{\circ}(\text { cathode })-E_{\text {red }}^{\circ}(\text { anode })\right]\end{aligned}$

4.Nernst Equation: $\mathrm{E}=\mathrm{E}^{\circ}-\frac{\mathrm{RT}}{\mathrm{nF}} \ln Q$

5. Nernst Equation at 298 K: $\mathrm{xA}+\mathrm{yB} \xrightarrow{\mathrm{ne}^{-}} \mathrm{mC}+\mathrm{nD}$
The emf can be calculated as

$\text { Ecell }=\mathrm{E}^{\circ} \text { cell }-\frac{0.059}{\mathrm{n}} \log \frac{[\mathrm{C}]^{\mathrm{m}}[\mathrm{D}]^{\mathrm{n}}}{[\mathrm{~A}]^x[\mathrm{~B}]^{\mathrm{y}}}$

6. Molar Conductivity Formula: $\wedge_{\mathrm{m}}=\kappa \times \frac{1000}{\mathrm{c}}$

7. Equivalent Conductivity Formula: $\wedge_{\text {eq }}=\frac{1000 \times \kappa}{\mathrm{N}}$

Solutions

Mass $\%$ of a component $=\frac{\text { Mass of the component in the solution }}{\text { Total mass of the solution }} \times 100$

Volume $\%$ of a component $=\frac{\text { Volume of the component }}{\text { Total volume of solution }} \times 100$

Mass by Volume $\%$ of a component $=\frac{\text { Mass of the component }}{\text { Total volume of solution }} \times 100$

Parts per million $=\frac{\text { Number of parts of the component }}{\text { Total number of parts of all components of the solution }} \times 10^6$

Mole fraction of a component $=\frac{\text { Number of moles of the component }}{\text { Total number of moles of all the components }}$

Molarity: $(M)=\frac{\text { No. of Moles of Solutes }}{\text { Volume of Solution in Liters }}$

Molality: $(m)=\frac{\text { No. of Moles of Solutes }}{\text { Mass of solvent in } \mathrm{kg}}$

Raoult’s Law for a Binary Solution:

$\left(P_T\right)=P_A^o X_A+P_B^o X_B$ ($\begin{aligned} & P_A=P_A^o X_A \\ & P_B=P_B^o X_B \\ & P_T=P_A+P_B\end{aligned}$)

Elevation in Boiling Point Formula: $\Delta \mathrm{T}_{\mathrm{b}}=\mathrm{K}_{\mathrm{b}} \times \frac{\mathrm{w}}{\mathrm{M}} \times \frac{1000}{\mathrm{~W}}$

Depression in Freezing Point Formula: $\Delta T_f=K_f \times \frac{w}{M} \times \frac{1000}{W}$

Osmotic Pressure Formula: $\Pi=C R T$

$\begin{aligned} & \mathrm{i}=\frac{\text { Observed number of solute particles }}{\text { Number of particles initially taken }} \\ & \mathrm{i}=\frac{\text { Observed value of colligative property }}{\text { Theoretical value of colligative property }}\end{aligned}$

Chemical kinetics

Unit of Average Rate: Unit of average velocity $=\frac{\text { Unit of concentration }}{\text { Unit of time }}=\frac{\text { mole }}{\text { litre second }}=$ mole litre $^{-1}$ second $^{-1}$

aA+bBcC+dD

Rate of Reaction w.r.t. A: Rate w.r.t. $[\mathrm{A}]=-\frac{\mathrm{d}[\mathrm{A}]}{\mathrm{dt}} \times \frac{1}{\mathrm{a}}$

Rate of Reaction w.r.t. B: Rate w.r.t. $[B]=-\frac{d[B]}{d t} \times \frac{1}{b}$

Rate of Reaction w.r.t. C: Rate w.r.t. $[\mathrm{C}]=\frac{\mathrm{d}[\mathrm{C}]}{\mathrm{dt}} \times \frac{1}{\mathrm{c}}$

Rate of Reaction w.r.t. D: Rate w.r.t. $[\mathrm{D}]=\frac{\mathrm{d}[\mathrm{D}]}{\mathrm{dt}} \times \frac{1}{\mathrm{~d}}$

Rate Law: $\mathrm{R} \propto[\mathrm{A}]^{\mathrm{p}}[\mathrm{B}]^{\mathrm{q}}$

Unit of Rate Constant-

The differential rate expression for $\mathrm{n}^{\text {th }}$ order reaction is as follows:

$-\frac{\mathrm{dx}}{\mathrm{dt}}=\mathrm{k}(\mathrm{a}-\mathrm{x})^{\mathrm{n}}$ or $\mathrm{k}=\frac{\mathrm{dx}}{(\mathrm{a}-\mathrm{x})^{\mathrm{n}} \mathrm{dt}}=\frac{(\text { concentration })}{(\text { concentration })^{\mathrm{n}} \text { time }}=(\text { conc. })^{1-\mathrm{n}}$ time $^{-1}$

Rate Constant for First-Order Reaction:

$\displaystyle k=\frac{2.303}{t} \log \frac{[\mathrm{R}]_0}{[\mathrm{R}]}$

Half-Life of First-Order Reaction:

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

Half-Life of General nth-Order Reaction:

$\mathrm{t}_{\frac{1}{2}} \propto[\mathrm{~A}]_0^{1-\mathrm{n}}$

It is to be noted that the above formula is applicable for any general nth-order reaction except n=1.

Arrhenius Equation: $\mathrm{k}=\mathrm{Ae}^{-\mathrm{Ea} / \mathrm{RT}}$

Two-Temperature Form of Arrhenius Equation:

$\log \frac{\mathrm{K}_2}{\mathrm{~K}_1}=\frac{\mathrm{Ea}}{2.303 \mathrm{R}}\left[\frac{1}{\mathrm{~T}_1}-\frac{1}{\mathrm{~T}_2}\right]$

JEE Main Formulas of Inorganic Chemistry

Coordination Compounds

Effective Atomic Number (EAN):

$\mathrm{EAN}=Z-O+2 L$

Where:

$\mathbf{Z}=$ Atomic number of the central metal atom/ion

$\mathbf{O}=$ Oxidation state of the metal atom/ion

L = Number of ligands (or donor atoms) $\times$ number of electrons donated per ligand

Crystal Field Stabilisation Energy (CFSE):

Octahedral:

$\mathrm{CFSE}=(-0.4 x+0.6 y) \Delta_0$

Tetrahedral:

$\mathrm{CFSE}=(-0.6 x+0.4 y) \Delta_t$

where $x=t_2 g$ electrons, $y=$ e_g electrons

d- & f-Block Elements

Magnetic Moment: $\mu=\sqrt{n(n+2)} \mathrm{BM}$

Chemical Bonding and Molecular Structure

Formal Charge:

$\text { F.C. }=V-N-\frac{B}{2}$

( $\mathrm{V}=$ valence electrons, $\mathrm{N}=$ non-bonding, $\mathrm{B}=$ bonding electrons)

Bond Order (Molecular Orbital Theory):

$\text { Bond Order }=\frac{\left(N_b-N_a\right)}{2}$

Dipole Moment:

$\mu=q \times d$

( $q=$ charge,$d=$ distance between charges)

JEE Main Formulas: Organic Chemistry

Some Basic Principles of Organic Chemistry

Application of Inductive Effect

The decreasing -I effect or increasing +I effect order is as follows:

$\begin{aligned} & -\mathrm{NH}_3^{+}>-\mathrm{NO}_2>-\mathrm{SO}_2 \mathrm{R}>-\mathrm{CN}>-\mathrm{SO}_3 \mathrm{H}>-\mathrm{CHO}>-\mathrm{COR}>-\mathrm{COOH} \\ & >-\mathrm{F}>-\mathrm{COCl}>-\mathrm{CONH}_2>-\mathrm{Cl}>-\mathrm{Br}>-\mathrm{I}>-\mathrm{OR}>-\mathrm{OH} \\ & >-\mathrm{NR}_2>-\mathrm{NH}_2>-\mathrm{C}_6 \mathrm{H}_5>-\mathrm{CH}=\mathrm{CH}_2>-\mathrm{H}\end{aligned}$

Degree of Unsaturation (DU or IHD):

$\mathrm{DU}=\frac{2 C+2-H+N-X}{2}$

( $\mathrm{C}=$ carbon, $\mathrm{H}=$ hydrogen, $\mathrm{N}=$ nitrogen, $\mathrm{X}=$ halogen)

Hydrocarbons

Alkanes: $C_n H_{2 n+2}$

Alkenes: $C_n H_{2 n}$

Alkynes: $C_n H_{2 n-2}$

Specific rotation (optical activity): $[\alpha]=\frac{\alpha}{l c}$

$[\alpha]=$ Specific rotation

$\alpha=$ Observed rotation

$l=$ Length of the polarimeter tube in dm

$c=$ Concentration of the solution in $\mathrm{g} / \mathrm{mL}$

How to Use These Top Formulas Effectively

Having a list of JEE Main Chemistry formulas for 2027 is of no use when aspirants do not use them properly. Correct use of these formulas helps in improving the score in JEE Main.

• Don't just memorise; understand the derivation once. If you understand where the Nernst equation or Van der Waals equation comes from, you'll never forget the formula, even under exam stress.

• Group formulas by chapter, not randomly. Your brain retrieves information faster when it's organised contextually; this is why the list above is grouped by topic rather than alphabetically.

• Practice unit conversions alongside formulas. A huge number of silly mistakes in JEE Main Chemistry come from mismatched units (e.g., using T in °C instead of Kelvin in gas law problems).

• Revise this sheet in the last 15 days before the exam. Formula sheets are most powerful as a rapid-recall tool close to exam day, not as a primary learning resource months in advance.

• Solve previous 10 years' JEE Main papers to see how each formula is actually tested this reveals patterns examiners repeat year after year.

Also Read: JEE Main 2027 Notes PDF: Formulas, Important Concepts & Quick Revision

Best Books for JEE Main Chemistry 2027 Preparation

Selecting proper JEE Main books will make the preparation of chemistry easy and systematic. Students must select such books that have clear explanations for concepts and sufficient numerical problems for practice.

• NCERT Chemistry Class 11 & 12

• N. Awasthi - Problems in Physical Chemistry

• O.P. Tandon - Organic Chemistry

• J.D. Lee - Concise Inorganic Chemistry

• JEE Main Chapter-wise/Year-wise PYQ book