Class 12 Chemistry Chapter 1 Solutions packs over 25 numerical formulae into a single chapter, the densest formula load in the Physical Chemistry block of the 2026-27 NCERT. The chapter drives nearly every concentration, colligative-property, and van't Hoff numerical asked across CBSE Boards, JEE Main, and NEET. This page hosts the complete formula sheet PDF, quick-fact cards, and a when-to-use decision tree.
- CBSE Weightage: 5-7 marks (usually one short answer plus one numerical)
- JEE Main Weightage: 3-4% (2-3 questions per paper)
- NEET Weightage: 2-3 questions per year
You can find the complete Formula Sheet for Solutions including every concentration term, colligative-property relation, and van't Hoff correction as needed for CBSE Boards 2026-27 in the article below.
This Formula Sheet is curated by Chemistry subject experts, mapped to the 2026-27 NCERT, and refined against the last five years of CBSE Board, JEE Main, and NEET papers.
Also Check:
How will Collegedunia's Formula Sheet Help You with Solutions Class 12 Chemistry?
This Formula Sheet gathers every relation you need to attempt any numerical from the Solutions chapter without flipping pages, organised in the order the 2026-27 NCERT introduces them.
- 2026-27 NCERT Alignment: Every concentration term, Raoult's law statement, and colligative-property formula matches the current syllabus. Abnormal molar mass and the van't Hoff factor are retained intact.
- SI Units Beside Every Formula: Each row shows the formula plus the SI unit of the result, so you can sanity-check a numerical without re-deriving the dimension.
- Decision Tree Included: The "when to use which formula" block tells you whether to pick molality or molarity, ΔTb or ΔTf, π or osmotic-pressure-with-van't-Hoff in a given question.
- Quick-Fact Cards for MCQs: Five atomic numerical facts (Kb of water, Kf of water, ideal gas constant, etc.) sit in a colour-coded card row for last-minute recall.
Solutions Video Walkthrough
Source: Magnet Brains on YouTube
Solutions Class 12 Chemistry Complete Formula Reference
The table lists every formula introduced in Chapter 1 of the 2026-27 NCERT, mapped to its NCERT section reference and the typical question setup where it appears. Read it once alongside the textbook on day one, then again as a 30-minute one-shot before any test.
| Concept | Formula | SI Unit | NCERT Section | Typical Use |
|---|---|---|---|---|
| Mass percent | %(w/w) = msolutemsolution × 100 | % | 1.2.1 | Alloy and aqueous mixture |
| Volume percent | %(V/V) = VsoluteVsolution × 100 | % | 1.2.1 | Ethanol-water type liquid mixtures |
| Mass by volume percent | %(w/V) = msoluteVsolution × 100 | g/100 mL | 1.2.1 | Pharmaceutical concentration |
| Parts per million | ppm = msolutemsolution × 106 | - | 1.2.1 | Trace pollutants, hard water |
| Mole fraction | xA = nAnA + nB | - | 1.2.2 | Raoult's law substitutions |
| Molarity | M = nsoluteVsolution (L) | mol/L | 1.2.3 | Titrations, stoichiometry |
| Molality | m = nsolutemsolvent (kg) | mol/kg | 1.2.4 | Colligative-property numericals |
| Henry's law | p = KH · x | bar (Kh) | 1.4 | Gas-in-liquid solubility |
| Raoult's law (volatile solute) | ptotal = pA0 xA + pB0 xB | bar | 1.5.1 | Two-volatile-liquid mixtures |
| Raoult's law (non-volatile solute) | psolution = pA0 · xA | bar | 1.5.2 | Sugar / urea in water |
| Relative lowering of vapour pressure | pA0 - pApA0 = xB | - | 1.6.1 | Molar-mass determination by VP |
| Elevation of boiling point | Δ Tb = Kb · m | K | 1.6.2 | Solvent boiling-point shift |
| Depression of freezing point | Δ Tf = Kf · m | K | 1.6.3 | Antifreeze, salt-on-ice numericals |
| Osmotic pressure | π = C R T | bar | 1.6.4 | Biological and dilute solutions |
| Osmotic pressure (mass form) | π = w2 R TM2 V | bar | 1.6.4 | Molar mass of macromolecule |
| van't Hoff factor | i = observed colligative propertycalculated colligative property | - | 1.7 | Electrolyte / associating solute |
| Modified ΔTb | Δ Tb = i · Kb · m | K | 1.7 | NaCl, CaCl₂ in water |
| Modified ΔTf | Δ Tf = i · Kf · m | K | 1.7 | Ionic salts depressing FP |
| Modified osmotic pressure | π = i C R T | bar | 1.7 | Strong electrolyte solutions |
| Degree of dissociation | α = i - 1n - 1 | - | 1.7 | NaCl, K₂SO₄ ionisation extent |
| Degree of association | α = 1 - i1 - 1n | - | 1.7 | Benzoic acid in benzene |
| Abnormal molar mass | Mobserved = Mnormali | g/mol | 1.7 | Dimerisation / dissociation cases |
| Molarity-density link | m = 1000 · M1000 · d - M · M2 | mol/kg | 1.2 | Convert M to m given density |
| Dilution equation | M1 V1 = M2 V2 | - | 1.2.3 | Volumetric dilution problems |
| Mole fraction sum | xA + xB = 1 | - | 1.2.2 | Two-component sanity check |
Memorising these 25 formulae alone covers nearly every Solutions numerical asked in CBSE, JEE Main, and NEET between 2021 and 2025.
When to Use Which Formula in Solutions Class 12 Chemistry
Picking the right formula is the difference between full marks and a silly slip. The decision tree below tells you which expression to apply based on what the question hands you.
- Question gives mass of solute and solvent, asks concentration: compute molality m if temperature might change; molarity M only if volume is held constant.
- Question gives vapour pressure of pure and of solution: use relative lowering p0 - pp0 = xB , then solve for the solute's mole fraction or molar mass.
- Question hands you a boiling-point or freezing-point shift: use Δ T = K · m for non-electrolytes; multiply by i for any salt that ionises.
- Question involves a polymer, protein, or any large molecule: default to osmotic pressure π = CRT , because Δ Tb and Δ Tf are too small to measure for high M .
- Question asks "abnormal" molar mass: divide the calculated M by i to get the observed value; if i > 1 the solute dissociates, if i < 1 it associates.
- Question mixes molarity and molality: use the molarity-density link to convert between the two without re-doing the mole calculation from scratch.
Solutions Class 12 Chemistry Quick-Fact Cards for MCQ Recall
These five atomic facts are the ones the MCQ writers reach for most often. Glance over them the morning of any test; every entry has been asked in JEE Main or NEET in the last five years.
Symbol Glossary for Solutions Class 12 Chemistry Formulae
Every variable used above, decoded in one row. Bookmark this if you keep getting confused between molarity M and molar mass M2 .
| Symbol | What it means | SI Unit |
|---|---|---|
| xA, xB | Mole fractions of solvent A and solute B | - |
| M | Molarity of the solution | mol L-1 |
| m | Molality of the solution | mol kg-1 |
| pA0 | Vapour pressure of pure solvent A | bar |
| pA | Vapour pressure of A in solution | bar |
| KH | Henry's law constant | bar |
| Kb, Kf | Molal elevation and depression constants of the solvent | K kg mol-1 |
| π | Osmotic pressure | bar or atm |
| i | van't Hoff factor | - |
| α | Degree of dissociation or association | - |
| n | Number of particles produced per formula unit | - |
| M2 | Molar mass of solute | g mol-1 |
A single symbol mix-up between molarity (M) and molar mass (M2) is the single most-marked mistake in CBSE 2024 and 2025 Solutions numericals.
Solutions Top 5 Formulae Recap: Quick PYQ Map for Class 12th Chemistry
The five formulae below carry the largest share of marks in CBSE Board, JEE Main, and NEET papers from 2021 to 2025. The complete year-wise PYQ map sits on the dedicated Collegedunia NCERT Solutions page for this chapter.
| Formula | Most-recent exam appearance |
|---|---|
| Δ Tf = i Kf m | CBSE 2025 (3 marks), NEET 2024 (1 Q) |
| π = CRT | JEE Main 2025 (Session 1), NEET 2025 |
| p = KH x | CBSE 2024 (2 marks), JEE Main 2024 |
| i = (iobs) / (icalc) | CBSE 2023 (5 marks), NEET 2023 |
| p0 - pp0 = xB | CBSE 2025 (3 marks), JEE Main 2024 |
Full year-wise PYQ map: Solutions Class 12 Chemistry NCERT Solutions
One-Shot Revision Tips for Solutions Class 12th Chemistry
The night-before revision strategy that works: layer the formula sheet on top of two or three reference numericals, not on top of the textbook. Treat the sheet as a checklist you tick off as you recall every term.
- Lock the four colligative properties as a single block. Relative VP lowering, ΔTb, ΔTf, and osmotic pressure rise and fall together; if you forget one, derive it from the proportionality ∝ molality .
- Memorise the two water constants. Kb = 0.512 and Kf = 1.86 (units K kg mol-1) appear in roughly 70% of CBSE numericals.
- Practise unit conversion between molarity and molality. The conversion uses solution density, and CBSE 2025 set 55/1/1 leaned on this as a 2-mark sub-question.
- Treat the van't Hoff factor as the universal multiplier. If the solute is ionic or associating, every colligative formula picks up a factor of i . Forgetting this single multiplication has cost more students Solutions marks than any other slip.
- Use π = CRT for any macromolecule numerical. Polymers, haemoglobin, and proteins all default to osmotic pressure because their molar mass is too high for ΔTb or ΔTf to be measurable.
Formulas Covered in Class 12 Chemistry Chapter 1 Solutions Formula Sheet
This Formula Sheet hosts every relation a Class 12 student needs from the 2026-27 NCERT Chapter 1 syllabus. The concentration block carries mass percent, volume percent, ppm, mole fraction, molarity, molality, plus the molarity-to-molality conversion using density. The vapour-pressure block lists Henry's law ( p = KH x ) and both forms of Raoult's law. The colligative-property block carries relative lowering of vapour pressure, elevation in boiling point ( Δ Tb = i Kb m , with Kb = 0.512 K kg mol-1 for water), depression in freezing point ( Δ Tf = i Kf m , with Kf = 1.86 K kg mol-1 for water), and osmotic pressure ( π = i C R T ). The final block decodes the van't Hoff factor with degree-of-dissociation ( α = (i-1)/(n-1) ) and degree-of-association formulae, plus the abnormal molar mass relation Mobs = Mnormal/i .
Solutions Top 5 Concept Recall for Class 12 Chemistry
Formulae alone do not solve numericals; you also need the five concepts below ready in active memory. The complete topic-by-topic walkthrough sits on the Notes page.
- Henry's law: partial pressure of a gas above a liquid is proportional to its mole fraction in the liquid; KH falls with rising temperature.
- Raoult's law: the vapour pressure of any component over a solution equals its pure-component VP times its mole fraction in solution.
- Ideal vs non-ideal solutions: ideal solutions obey Raoult's law at all compositions; non-ideal solutions show positive (acetone-ethanol) or negative (chloroform-acetone) deviations.
- Azeotropes: non-ideal mixtures that boil at a fixed composition, so fractional distillation cannot separate them.
- Osmosis and reverse osmosis: solvent flow from low to high concentration across a semipermeable membrane; reverse osmosis (used in desalination) pushes water the opposite way under applied pressure.
Full topic-by-topic walkthrough: Solutions Class 12 Chemistry Notes
Solutions Weightage Compared Across Class 12 Chemistry Chapters
The visual below maps the typical CBSE marks distribution across all 10 chapters of the 2026-27 Class 12 Chemistry NCERT, averaged over the last five board papers. Chapter 1 sits in the upper band, justifying the formula-heavy revision it demands.
Related Links:
- Solutions Class 12 Chemistry Handwritten Notes
- Solutions Class 12 Chemistry NCERT Exemplar Solutions
More Solutions Chemistry Class 12 Resources
NCERT Formula Sheet for Class 12 Chemistry: All Chapters
Use the table below to jump to the Formula Sheet for any other chapter in the Class 12 Chemistry NCERT.
| Chapter | Resource |
|---|---|
| Chapter 2 | Electrochemistry Formula Sheet |
| Chapter 3 | Chemical Kinetics Formula Sheet |
| Chapter 4 | The d- and f-Block Elements Formula Sheet |
| Chapter 5 | Coordination Compounds Formula Sheet |
| Chapter 6 | Haloalkanes and Haloarenes Formula Sheet |
| Chapter 7 | Alcohols, Phenols and Ethers Formula Sheet |
| Chapter 8 | Aldehydes, Ketones and Carboxylic Acids Formula Sheet |
| Chapter 9 | Amines Formula Sheet |
| Chapter 10 | Biomolecules Formula Sheet |
Solutions Class 12 Chemistry Formula Sheet FAQs
Ques. Where can I download the Solutions Class 12 Chemistry Formula Sheet PDF?
Ans. You can download the Solutions Class 12 Chemistry Formula Sheet PDF directly from this page. Both Normal and HD versions are free and cover every formula introduced in the 2026-27 NCERT chapter.
Ques. Is this Formula Sheet aligned with the 2026-27 NCERT?
Ans. Yes. The sheet reflects the current 2026-27 syllabus for Class 12 Chemistry. The Solutions chapter retains every concentration term, Raoult's law statement, colligative property, and van't Hoff correction from the previous edition.
Ques. How many pages is the Class 12th Chemistry Solutions Formula Sheet PDF?
Ans. The Formula Sheet PDF runs approximately 8 pages and covers 25-plus formulae, the four colligative properties, Henry's and Raoult's laws, the van't Hoff factor, and a one-shot revision strip.
Ques. How many formulae are in the Solutions chapter of Class 12 Chemistry?
Ans. The chapter introduces 25-plus formulae, grouped into concentration terms (7), Henry's and Raoult's laws (4), colligative properties (8), van't Hoff and abnormal molar mass (4), and unit-conversion shortcuts (2).
Ques. Which is the most important formula in Solutions Class 12?
Ans. The depression of freezing point Δ Tf = i Kf m and the osmotic pressure π = i C R T are the two highest-yield formulae. Together they account for over 40% of the numericals asked in CBSE Boards, JEE Main, and NEET between 2021 and 2025.
Ques. What is the CBSE weightage of Chapter 1 Solutions in Class 12 Chemistry?
Ans. Solutions carries 5 to 7 marks in the CBSE Class 12 Chemistry Board exam, usually split as one short-answer question and one numerical. The chapter also draws 3-4% in JEE Main and 2-3 questions per NEET paper.
Ques. How is molarity different from molality, and which one do colligative-property numericals need?
Ans. Molarity is moles per litre of solution and changes with temperature; molality is moles per kilogram of solvent and is temperature-independent. Every colligative-property numerical (ΔTb, ΔTf, relative VP lowering) uses molality. Only the dilution equation and osmotic pressure π = CRT use molarity.
Ques. Why does NaCl have a van't Hoff factor of 2?
Ans. NaCl dissociates completely in water into one Na⁺ and one Cl⁻, producing two particles per formula unit. Since i measures the observed number of particles relative to the formula-unit count, NaCl gives i = 2 for full dissociation. Real solutions show i slightly below 2 because of ion pairing.
Ques. What is the formula for the relative lowering of vapour pressure?
Ans. For a non-volatile solute, the relative lowering of vapour pressure equals the mole fraction of solute: (p1∘ - p1)/p1∘ = x2 . This is the direct consequence of Raoult's law and is the canonical CBSE 3-mark numerical for finding the molar mass of an unknown non-volatile solute (sugar, urea, glycerol).
Ques. What is the formula for osmotic pressure and when do I include the van't Hoff factor?
Ans. Osmotic pressure for a non-electrolyte is π = CRT where C is the molar concentration in mol L-1 and R = 0.0821 L atm K-1 mol-1 (or 0.0831 L bar K-1 mol-1). For an electrolyte like NaCl or K2SO4, multiply by the van't Hoff factor: π = i C R T . Macromolecules (proteins, polymers) default to osmotic pressure because Δ Tb and Δ Tf are too small to measure.
Ques. What are the Kb and Kf values for water?
Ans. For water, the molal boiling-point elevation constant Kb = 0.512 K kg mol-1 and the molal freezing-point depression constant Kf = 1.86 K kg mol-1. Both carry the same unit, K kg mol-1. Memorise these two values, since roughly 70% of CBSE colligative-property numericals from Chapter 1 use water as the solvent.
Ques. How do I compute the degree of dissociation from the van't Hoff factor?
Ans. If a solute dissociates into n particles with degree of dissociation α , then i = 1 + (n-1)α , so α = (i-1)/(n-1) . For example, for K2SO4 (n = 3) with an observed i = 2.4 , α = (2.4-1)/(3-1) = 0.7 , meaning 70% dissociation. For association (e.g. benzoic acid dimer in benzene), α = (1 - i) / (1 - 1/n) .
Comments