Chemistry can make or break your Re-NEET 2026 score — and the difference between a 130 and a 160 in Chemistry almost always comes down to one thing: how well you know your formulas and reactions on exam day.
This Re-NEET 2026 Chemistry formula sheet covers the most tested equations and reactions across Physical, Organic, and Inorganic Chemistry — with worked examples under each formula so you know exactly how to apply them in a question, not just recognise them on paper.
Bookmark this. Revise it every morning. By June 21, these should feel like second nature.
Table of Contents
How to Use This Re-NEET 2026 Chemistry Formula Sheet
Don’t just read through this once. For each formula:
- Read the formula and what each variable means
- Study the worked example below it
- Solve 2–3 PYQs from that formula before moving on
- Write the formula on a flashcard for daily morning revision
This active approach is what converts a formula sheet into actual exam marks. If you want the complete subject-wise priority breakdown, the Re-NEET 2026 Chemistry strategy article maps out which chapters to cover first based on weightage.
Physical Chemistry Formulas Re-NEET 2026 — Most Tested Equations
Physical Chemistry is formula-heavy and numerical-driven. These are the equations that appear most consistently in NEET papers.
1. Mole Concept
Formula:
Number of moles (n) = Given mass (w) / Molar mass (M)
Number of molecules = n × 6.022 × 10²³
Worked Example: How many moles are present in 44 g of CO₂? (Molar mass of CO₂ = 44 g/mol)
n = 44 / 44 = 1 mole
Number of molecules = 1 × 6.022 × 10²³ = 6.022 × 10²³ molecules
2. Ideal Gas Equation
Formula:
PV = nRT
Where: P = pressure (atm), V = volume (L), n = moles, R = 0.0821 L·atm/mol·K, T = temperature (K)
Worked Example: What volume does 2 moles of an ideal gas occupy at 27°C and 1 atm pressure?
T = 27 + 273 = 300 K V = nRT/P = (2 × 0.0821 × 300) / 1 = 49.26 L
3. Raoult’s Law (Solutions)
Formula:
P_solution = x_solvent × P°_solvent
Relative lowering of vapour pressure = (P° − P) / P° = x_solute
Worked Example: The vapour pressure of pure water at 25°C is 23.8 mmHg. What is the vapour pressure of a solution containing 0.1 mole fraction of glucose?
x_solvent = 1 − 0.1 = 0.9 P_solution = 0.9 × 23.8 = 21.42 mmHg
4. Rate Law & Rate Constant (Chemical Kinetics)
Formula:
Rate = k[A]^m [B]^n
For first-order reaction: k = (2.303 / t) × log([A]₀ / [A]t)
Half-life of first-order reaction: t₁/₂ = 0.693 / k
Worked Example: The rate constant of a first-order reaction is 0.693 min⁻¹. What is its half-life?
t₁/₂ = 0.693 / 0.693 = 1 minute
5. Nernst Equation (Electrochemistry)
Formula:
E_cell = E°_cell − (0.0591 / n) × log Q
Where: n = number of electrons transferred, Q = reaction quotient
Formula for EMF at standard conditions:
E°_cell = E°_cathode − E°_anode
Worked Example: Calculate E°_cell for Zn | Zn²⁺ || Cu²⁺ | Cu, given E°(Zn²⁺/Zn) = −0.76V and E°(Cu²⁺/Cu) = +0.34V.
E°_cell = 0.34 − (−0.76) = +1.10 V
6. Gibbs Free Energy & Equilibrium
Formulas:
ΔG = ΔH − TΔS
ΔG° = −RT ln K = −2.303 RT log K
ΔG° = −nFE°_cell
Worked Example: If ΔG° = −ve, what does it tell you about the reaction?
ΔG° < 0 → K > 1 → reaction is spontaneous and products are favoured at equilibrium
This is a classic NEET reasoning question — know the sign logic cold.
7. pH Formulas
Formulas:
pH = −log[H⁺]
pOH = −log[OH⁻]
pH + pOH = 14 (at 25°C)
For weak acid: [H⁺] = √(Ka × C)
Worked Example: What is the pH of a 0.01 M HCl solution?
[H⁺] = 0.01 = 10⁻² pH = −log(10⁻²) = 2
For weak acid (0.1 M acetic acid, Ka = 1.8 × 10⁻⁵):
[H⁺] = √(1.8 × 10⁻⁵ × 0.1) = √(1.8 × 10⁻⁶) = 1.34 × 10⁻³ pH = −log(1.34 × 10⁻³) ≈ 2.87
The Physical Chemistry numericals for NEET guide covers the full problem-solving approach for each of these chapters in detail.
Organic Chemistry Equations Re-NEET 2026 — Most Tested Reactions
Organic Chemistry in NEET is less about derivations and more about recognising reaction types, reagents, and products. Know these cold.
1. SN1 vs SN2 — Key Difference
SN1: Tertiary substrate + polar protic solvent → carbocation intermediate → racemic mixture SN2: Primary substrate + polar aprotic solvent → one-step backside attack → inversion of configuration
NEET Application: Which substrate undergoes SN1 fastest? (a) CH₃Cl (b) (CH₃)₂CHCl (c) (CH₃)₃CCl (d) CH₃CH₂Cl
Answer: (c) (CH₃)₃CCl — tertiary, most stable carbocation formed
2. Lucas Test
Primary alcohol + Lucas reagent (ZnCl₂/conc. HCl) → No immediate turbidity (reacts slowly) Secondary alcohol → Turbidity in 5 minutes Tertiary alcohol → Immediate turbidity
NEET Application: A colourless alcohol gives immediate turbidity with Lucas reagent. It is:
Answer: Tertiary alcohol — the immediate cloudiness is the product (alkyl chloride) which is insoluble in the reagent.
3. Aldol Condensation
Aldehyde/ketone with α-hydrogen + dilute NaOH → β-hydroxy aldehyde/ketone (aldol product) On heating → α,β-unsaturated carbonyl compound (elimination product)
NEET Application: Acetaldehyde (CH₃CHO) undergoes aldol condensation. The product after elimination is:
CH₃CHO + CH₃CHO → CH₃CH(OH)CH₂CHO (aldol) → CH₃CH=CHCHO (crotonaldehyde) on heating
4. Cannizzaro Reaction
Aldehydes with NO α-hydrogen + conc. NaOH → one molecule oxidised (to acid) + one reduced (to alcohol)
NEET Application: HCHO undergoes Cannizzaro reaction. Products are:
HCHO → HCOO⁻Na⁺ (sodium formate) + CH₃OH (methanol)
5. Hofmann Bromamide Reaction
RCONH₂ + Br₂ + NaOH → RNH₂ (primary amine with one less carbon)
NEET Application: Benzamide undergoes Hofmann bromamide reaction. Product is:
C₆H₅CONH₂ → C₆H₅NH₂ (aniline) — carbon chain decreases by 1
6. Diazotisation & Coupling
ArNH₂ + NaNO₂ + HCl (0–5°C) → ArN₂⁺Cl⁻ (diazonium salt) ArN₂⁺ + C₆H₅OH (alkaline) → azo compound (orange/red dye)
NEET Application: Aniline reacts with NaNO₂/HCl at 0°C. The product is:
Benzene diazonium chloride (C₆H₅N₂⁺Cl⁻)
For a complete chapter-wise Organic Chemistry breakdown, the Organic Chemistry for Re-NEET article is the most thorough resource — covers every chapter with PYQ weightage.
Most Tested Chemistry Reactions NEET 2026 — Inorganic
Inorganic Chemistry Reactions NEET Last Minute — Can’t-Skip Reactions
Inorganic Chemistry in NEET is dominated by p-block, d-block, and coordination compound reactions. These come up every single year.
1. Thermite Reaction
Fe₂O₃ + 2Al → Al₂O₃ + 2Fe + heat
NEET Application: Used in welding railway tracks. Al acts as a reducing agent. Product is molten iron.
2. Brown Ring Test (Nitrate Detection)
FeSO₄ + NO → [Fe(H₂O)₅NO]SO₄ (brown ring complex)
NEET Application: The brown colour is due to the formation of a nitrosonium complex of Fe²⁺. The ring forms at the interface of the two layers.
3. Disproportionation of Phosphorus
P₄ + 3NaOH + 3H₂O → PH₃ + 3NaH₂PO₂
NEET Application: Phosphorus undergoes both oxidation (+1 in NaH₂PO₂) and reduction (−3 in PH₃). This is a disproportionation reaction.
4. XeF₂, XeF₄, XeF₆ — Hybridisation & Shape
| Compound | Hybridisation | Shape |
|---|---|---|
| XeF₂ | sp³d | Linear |
| XeF₄ | sp³d² | Square planar |
| XeF₆ | sp³d³ | Distorted octahedral |
NEET Application: XeF₄ has 2 lone pairs on Xe. Shape is square planar. This is one of the most repeated NEET inorganic questions.
5. Colour of Transition Metal Ions (d-Block)
| Ion | Colour |
|---|---|
| Cu²⁺ | Blue |
| Fe³⁺ | Yellow/brown |
| Cr³⁺ | Green |
| Mn²⁺ | Light pink |
| Ni²⁺ | Green |
| Co²⁺ | Pink |
| Ti³⁺ | Purple |
NEET Application: Colour arises due to d-d transitions. Zn²⁺ is colourless because it has a completely filled d¹⁰ configuration — no d-d transition possible.
For a complete memorisation strategy for Inorganic Chemistry, including coordination compounds and p-block reactions, the Inorganic Chemistry for NEET 2027 guide has a proven memory framework that works for Re-NEET too.
How to Revise This Re-NEET 2026 Chemistry Formula Sheet in the Final Days
The Re-NEET 2026 Chemistry formula sheet above covers every high-frequency reaction type — but knowing them is only useful if you revise consistently. Don’t try to memorise everything in one sitting. Here is the revision rhythm that works:
- Morning (30 min): Flip through Physical Chemistry formulas — write each one from memory before checking
- After Chemistry sessions: Practise 10 reaction-based Organic MCQs using the reactions above
- Night (15 min): Read the Inorganic colour chart and reaction table once before sleeping
If you are following the Re-NEET 2026 19 day plan, plug this formula sheet into Days 7–11 (Chemistry phase) as your primary revision resource each morning.
One final thing — knowing formulas is only useful if you apply them correctly under pressure. Many students lose marks not because they don’t know the formula but because they misread the question. Make sure you have a clean strategy for avoiding negative marking in NEET before you sit your first full mock.
Frequently Asked Questions
Q: Which Physical Chemistry formulas are most important for Re-NEET 2026? A: Mole concept, ideal gas equation, rate law and half-life (Chemical Kinetics), Nernst equation (Electrochemistry), pH formulas, and Raoult’s Law are the highest-frequency Physical Chemistry formulas in NEET. Master these 6 areas and you cover the majority of Physical Chemistry marks.
Q: How many Organic Chemistry reactions should I memorise for Re-NEET 2026? A: Focus on 15–20 named reactions — especially Aldol condensation, Cannizzaro, Hofmann bromamide, diazotisation, and substitution mechanisms (SN1/SN2). Quality of understanding beats quantity of reactions memorised.
Q: Is Inorganic Chemistry formula-based or theory-based in NEET? A: Mostly theory and pattern-based — VSEPR shapes, oxidation states, colours of ions, and specific named reactions. There are fewer numerical formulas compared to Physical Chemistry, but the factual recall must be precise.
Q: How do I stop forgetting Chemistry formulas on exam day? A: Write each formula from memory every morning for 7 days straight. The act of recall — not just reading — is what builds lasting memory. Flashcards, not passive re-reading, is the method that works.
Q: Should I make my own Chemistry formula sheet or use a printed one? A: Make your own — handwritten. The act of writing the formulas yourself reinforces memory far more than reading a printed sheet. Use this article as the source and write it out in your own format.