Preparing for the Class 12 Chemistry board exam can feel stressful, especially in the last few days. At this stage, students are not looking to learn new concepts. They want quick clarity and safe revision. This page is created exactly for that purpose – quick, exam-focused revision without confusion.
Here, you will find class 12 chemistry formulas arranged chapter-wise, strictly based on the CBSE and NCERT syllabus. Only formulas, reactions, and key points that are relevant for board exams are included. Advanced-level content, shortcuts, and non-NCERT topics are clearly avoided to keep revision clean and reliable.
Who this guide is for
This guide helps students revise confidently in the final days and also helps parents understand what their child should focus on now. The structure is simple, exam-oriented, and suitable for chemistry formulas for last minute revision. If you are revising cbse class 12 chemistry formulas before the exam, this page is meant to support you calmly and clearly.
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Chapter-wise Class 12 Chemistry formulas for quick and safe CBSE board exam revision
Download Class 12 Chemistry Formulas PDF (Optional Support)
For students who prefer offline revision, a class 12 chemistry formulas pdf is provided as optional support. This PDF is self-created by Shiksha Nation, prepared carefully using NCERT chapters and board exam patterns. It is meant only for quick revision, not for learning new topics.
The PDF includes a clean class 12 chemistry formula list arranged chapter-wise, making it easy to revise during short breaks or before sleep. Parents can also use this PDF to help students revise calmly without switching between multiple books or websites.
How to Use This Formula Guide Before the Board Exam
In the last few days before the exam, your focus should be on revision, not new learning. Use this guide as a checklist to revise chemistry formulas for board exam in a calm and planned way. Read one chapter at a time and recall where each formula is used in numericals or theory questions.
Simple revision approach for students and parents
Students should first revise chapters with more calculations, then move to reactions and factual chapters. Parents can help by ensuring the student revises daily in short slots instead of long hours. This guide highlights important chemistry formulas class 12 students are expected to remember, without adding extra pressure or unnecessary content.
Physical Chemistry is scoring if formulas are clear and units are remembered correctly. Many board exam questions are directly based on applying formulas, not lengthy theory. This section covers physical chemistry formulas class 12 students revise repeatedly before the exam. Parents should note that regular practice of these formulas builds confidence and reduces exam fear.
These formulas are commonly used in numericals and short-answer questions.
Formula
Where it is used
Unit
Molarity (M) = moles of solute / volume of solution
Concentration calculations
mol/L
Molality (m) = moles of solute / mass of solvent
Colligative properties
mol/kg
Mole fraction (X) = moles of component / total moles
Vapour pressure problems
No unit
Raoult’s Law: P = X × P⁰
Solutions of volatile liquids
atm / bar
ΔTᵦ = Kᵦ × m
Elevation of boiling point
K
ΔT𝒻 = K𝒻 × m
Depression of freezing point
K
These solutions chapter formulas class 12 appear regularly in numericals.
Electrochemistry (Very High Weightage)
This chapter is important for both theory and numericals.
Formula
Where it is used
Unit
E°cell = E°cathode − E°anode
Cell potential calculation
Volt
E = E° − (0.059/n) log Q
Nernst equation
Volt
m = (Z × I × t)
Faraday’s first law
gram
Q = I × t
Charge passed
Coulomb
ΔG° = −nFE°cell
Relation of free energy
Joule
These electrochemistry formulas class 12 are often tested directly.
Chemical Kinetics (Short & Direct)
Focus on order, rate constant, and half-life.
Formula
Where it is used
Unit
Rate = Δ[C]/Δt
Reaction rate
mol L⁻¹ s⁻¹
k = (2.303/t) log (a/a−x)
First-order reactions
s⁻¹
t₁⁄₂ = 0.693/k
Half-life
seconds
k = Ae⁻ᴱᵃ/ᴿᵀ
Temperature effect
varies
These chemical kinetics formulas class 12 are simple but scoring.
Surface Chemistry (Concept + Formula Based)
Mostly short questions and definitions.
Formula / Term
Where it is used
Unit
x/m = kP¹⁄ⁿ
Freundlich adsorption isotherm
varies
Adsorption
Surface phenomenon
—
Catalyst
Rate enhancement
—
Colloid
Dispersed system
—
Revise these surface chemistry formulas and terms carefully for theory questions.
Student tip: Always revise formulas with units.
Parent tip: Encourage formula revision in short sessions to avoid overload.
Organic Chemistry Reactions & Formulas
Organic Chemistry often worries students because of many reactions and names. For the board exam, the focus is not on mechanisms or tricks. It is on reaction recognition, general equations, and correct products. This section covers organic chemistry reactions class 12 that are clearly mentioned in NCERT and frequently asked in exams.
Parents should understand that regular revision of reactions, even for short time daily, helps students feel more confident and reduces confusion.
Aldehydes, Ketones & Carboxylic Acids
This chapter carries good weightage and many direct questions.
Aldehydes (–CHO):
Oxidation of aldehydes forms carboxylic acids.
Example (general): R–CHO → R–COOH
Ketones (–CO–):
Ketones do not oxidise easily but undergo reduction to alcohols.
General form: R–CO–R′ → Secondary alcohol
Carboxylic Acids (–COOH):
Show acidic nature and form esters.
Esterification: R–COOH + R′–OH → Ester + Water
These aldehydes ketones reactions class 12 are often asked in short answers.
Amines
Amines are important for conversions and naming-based questions.
Classification: Primary, secondary, and tertiary amines
Basic nature: Due to presence of lone pair on nitrogen
These are amines reactions class 12 students must revise carefully.
Important Named Reactions (NCERT Only)
Named reactions are direct scoring if written correctly.
Aldol reaction: Aldehydes or ketones with α-hydrogen form β-hydroxy compounds
Cannizzaro reaction: Aldehydes without α-hydrogen form alcohol and acid
Friedel-Crafts reaction: Alkylation or acylation of aromatic rings
Kolbe reaction: Formation of hydrocarbons from sodium salts
Reimer-Tiemann reaction: Formation of aldehyde group in phenols
These named reactions class 12 chemistry are part of important reactions of class 12 chemistry.
Student tip: Focus on writing correct reactants and products.
Parent tip: Encourage revision through writing reactions, not just reading.
Inorganic Chemistry Formulas & Key Points
Inorganic Chemistry is mostly based on memory, definitions, and correct facts. Many students worry about formulas here, but it is important to understand that some chapters are concept-heavy and have limited formulas. This section highlights only the key formulas and points that are relevant for board exams, without adding extra information.
Parents can support students by helping them revise these points slowly and repeatedly, instead of trying to memorise everything at once.
d and f Block Elements
This chapter focuses more on properties than calculations.
Electronic configuration: Based on atomic number
Variable oxidation states: Common in transition elements
Magnetic behaviour:
Magnetic moment (μ) = √n(n + 2) BM
Colour of compounds: Due to d–d transitions
These are d and f block important points often asked in theory questions.
Coordination Compounds
This chapter has a mix of concepts and formulas.
Coordination number: Number of ligands attached to central metal
Werner’s theory: Primary and secondary valency
Effective Atomic Number (EAN):
EAN = Atomic number − oxidation state + electrons donated by ligands
Crystal Field Theory: Splitting of d-orbitals
These coordination compounds formulas class 12 are frequently tested.
Biomolecules
Biomolecules are mostly definition and structure based.
Carbohydrates: Glucose, sucrose, starch
Proteins: Amino acids linked by peptide bond
Nucleic acids: DNA and RNA
Only basic structures and classifications are required. These biomolecules chemistry formulas are limited but important.
Polymers
This chapter is short and scoring.
Addition polymers: Polyethylene, PVC
Condensation polymers: Nylon, Bakelite
Monomer → Polymer: Repeating unit concept
These polymers chemistry formulas are simple and direct.
Chemistry in Everyday Life
This chapter focuses on application-based learning.
Drugs: Analgesics, antiseptics, antibiotics
Soaps and detergents: Cleaning action
These chemistry in everyday life formulas are mostly name and use based.
Student tip: Focus on definitions and examples.
Parent tip: Help with daily revision of one chapter at a time.
Chapters With Maximum Formula Weightage
In the last phase of preparation, students should focus more on chapters where formulas are used directly in questions. This helps save time and improves accuracy during the exam. For most students, these chapters carry a higher share of important chemistry formulas class 12 and are safer to revise first.
High-priority chapters for formula revision
Chapters like Solutions, Electrochemistry, and Chemical Kinetics include many numericals and short answers based on formulas. Coordination Compounds also needs attention because definitions and formulas are often asked together. Revising these chapters properly helps students handle chemistry formulas for board exam with confidence.
Parents can support by ensuring the student revises these chapters calmly, without rushing or adding new topics at the last moment.
FAQs on Class 12 Chemistry Formulas
Q. How many formulas should I revise one day before exam?
One day before the exam, focus only on class 12 chemistry formulas you have already studied. Revise key formulas from high-weight chapters like Solutions, Electrochemistry, and Kinetics. Avoid learning anything new. Parents should help students stay calm and follow a short, planned revision schedule.
Q. Are these formulas enough for CBSE boards?
Yes, these cbse class 12 chemistry formulas are selected strictly from NCERT and cover what is usually required in board exams. However, students should also understand basic concepts and practice writing answers clearly. Formulas support answers but should not be the only focus.
Q. Which chapters have more numericals?
Chapters like Solutions, Electrochemistry, and Chemical Kinetics have more numerical-based questions. These chapters require regular practice of formulas and units. Revising formulas from these chapters helps students handle calculation-based questions with more confidence in the exam.
Q. Should I memorize reactions or understand them?
Students should first understand the type of reaction, then revise the general form. For chemistry formulas for last minute revision, focus on recognising reactants and products instead of detailed mechanisms. Parents can encourage students to write reactions once for better memory.
Q. Is this useful for CUET or NEET preparation?
This guide is mainly for CBSE board exams, but many class 12 chemistry formulas are also useful for CUET and NEET at the basic level. Students preparing for entrance exams should treat this as a foundation and revise additional exam-specific content separately.
