Class 12 Chemistry Chapter 1 Solutions carries 6 to 8 marks in the CBSE Board exam, 4 to 5% in JEE Main, and 2 to 3 questions per year in NEET, placing it among the highest-yield units of the Physical Chemistry block. This page hosts the official 2026-27 NCERT chapter PDF, its section map, the intext example inventory, and what changed during rationalisation.
- CBSE Weightage: 6–8 marks
- JEE Main Weightage: 4–5% (2–3 questions per paper)
- NEET Weightage: 2–3 questions per year
You can open the complete NCERT Book PDF for Chapter 1 Solutions below, along with the official section map, the Henry's law and Raoult's law derivations, and the colligative-property numerical templates as set by the NCERT for CBSE Boards 2026.
This NCERT Book PDF is sourced directly from the official ncert.nic.in archive, mapped to the 2026-27 rationalised syllabus, and cross-checked against the last five years of CBSE Board, JEE Main, and NEET question patterns.
Also Check:
- Solutions Class 12 Chemistry NCERT Solutions
- Solutions Class 12 Chemistry Notes
- Solutions Class 12 Chemistry Formula Sheet
Solutions NCERT Book: Section-by-Section Breakdown with Page Numbers
The 2026-27 NCERT print of Chapter 1 runs across 33 numbered pages (pages 1 to 33), split into nine numbered sub-sections plus a summary and exercise block. The breakdown below maps each section to its page range, the central idea it carries, and the kind of CBSE / JEE question it usually feeds. Read it before downloading so you know which page to bookmark first.
| Section | Title | Page Range | What It Covers |
|---|---|---|---|
| 1.1 | Types of Solutions | p. 2 – 3 | Solid, liquid, and gaseous solutions classified by phase of solute and solvent |
| 1.2 | Expressing Concentration of Solutions | p. 3 – 6 | Mass percent, volume percent, mole fraction, molarity, molality, ppm |
| 1.3 | Solubility | p. 6 – 11 | Solubility of solids and gases in liquids, Henry's law and its applications |
| 1.4 | Vapour Pressure of Liquid Solutions | p. 11 – 17 | Raoult's law for volatile and non-volatile solutes, ideal vs non-ideal behaviour |
| 1.5 | Ideal and Non-ideal Solutions | p. 17 – 19 | Positive and negative deviations, azeotropes (minimum and maximum boiling) |
| 1.6 | Colligative Properties and Determination of Molar Mass | p. 19 – 27 | Relative lowering of vapour pressure, elevation of boiling point, depression of freezing point, osmotic pressure |
| 1.7 | Abnormal Molar Masses | p. 27 – 29 | Van't Hoff factor, association and dissociation of solutes |
| — | Summary | p. 29 – 30 | One-page bullet recap of every concept; ideal for last-day revision |
| — | Exercises | p. 30 – 33 | 41 NCERT questions covering all sections (numericals + theory) |
The longest single section is 1.6 Colligative Properties at roughly 8 pages, and it is also the heaviest source of CBSE 5-markers and JEE Main numericals. Roughly 40% of every Chapter 1 question in the last five CBSE papers came from this section alone.
Solutions Video Chapter Walkthrough
Source: Magnet Brains on YouTube
Solutions NCERT Intext Examples and Their Sub-Topics
The NCERT prints nine intext worked examples inside Chapter 1, spaced through the sections so each major formula gets one demonstration. Solve every intext example before attempting the back-exercise. They are easier than the exercise questions and cover every formula template a student will face in the board paper.
| Example | Sub-topic | Skill Tested |
|---|---|---|
| Example 1.1 | Mass percent | Calculate mass % of ethylene glycol in water |
| Example 1.2 | Molarity | Find molarity of a NaOH solution from mass dissolved |
| Example 1.3 | Molality | Determine molality of a sulfuric acid solution given density |
| Example 1.4 | Henry's law | Compute partial pressure of dissolved gas using Henry's constant |
| Example 1.5 | Raoult's law (binary, volatile) | Vapour-pressure composition of a heptane-octane mixture |
| Example 1.6 | Relative lowering of vapour pressure | Find molar mass of an unknown non-volatile solute |
| Example 1.7 | Elevation of boiling point | Calculate molar mass of solute from observed Δ Tb |
| Example 1.8 | Depression of freezing point | Calculate molar mass from observed Δ Tf |
| Example 1.9 | Van't Hoff factor | Determine degree of dissociation of an electrolyte from i |
How will Collegedunia's NCERT Book PDF Help You with Solutions?
The official NCERT chapter is the single source of truth for the board paper. Here is what this Collegedunia page adds on top of the plain PDF link.
- 2026-27 Edition Mapping: The chapter has been re-paginated in the new edition. The section map above uses the latest page numbers so bookmarks land on the right page.
- Both PDF Versions: A lightweight Normal PDF for phone reading and an HD version for printing or projector use. Both are free and load directly from the official archive.
- Section-Wise Skill Map: Each section is tagged with the kind of CBSE / JEE question it typically produces, so you can plan section-by-section revision instead of linear reading.
- Rationalisation Audit: The kept-trimmed-removed table below tells you exactly what content from older editions still appears in 2026-27 and what does not, so no study time is wasted on dropped material.
Solutions Top 5 Formulae for Quick Recall
Five formulae account for nearly every numerical in the Solutions chapter. The complete master sheet with units, dimensional checks, and a "when to use which" decision tree sits on the dedicated Collegedunia Formula Sheet for the chapter. Use the mini-table below for a fast pre-PDF recap.
| Quantity | Formula |
|---|---|
| Molarity | M = moles of solutevolume of solution in L |
| Molality | m = moles of solutemass of solvent in kg |
| Henry's law | p = KH · x |
| Relative lowering of vapour pressure | p0 - psp0 = xsolute |
| Osmotic pressure (with Van't Hoff factor) | π = i · C · R · T |
Full master table: Solutions Class 12 Chemistry Formula Sheet
How to Read This Chapter — Recommended Sequence for Class 12th Boards
A 33-page chapter feels long if read linearly. Three passes is faster than one pass, and each pass has a different purpose. The split below assumes you have roughly four hours total spread across two evenings.
- Pass 1 — Skim (40 minutes): Read only the section headings, the formula boxes, and the chapter Summary on pages 29 to 30. Goal: build a mental table of contents.
- Pass 2 — Deep read with examples (2 hours): Read sections 1.1 to 1.7 in order. Work through every intext Example 1.1 to 1.9 with pen and paper as you reach each one. Do not skip examples; they are the closest match to board numerical templates.
- Pass 3 — Exercise attempt (1 hour 20 minutes): Attempt the 41 back-exercise questions in order. Mark every question you could not solve in under 5 minutes for a second-day revisit.
What Changed in Solutions for 2026-27 NCERT (Rationalisation Note)
The 2026-27 NCERT keeps almost all the core physical chemistry of the chapter intact, but two sub-topics from the older edition have been trimmed. Knowing what is no longer asked saves at least 30 minutes of wasted reading.
| Sub-topic | Status in 2026-27 NCERT | Asked in CBSE Boards? |
|---|---|---|
| Types of Solutions (solid / liquid / gas) | Kept | Yes (1-mark MCQ) |
| Concentration expressions (mass %, mole fraction, molarity, molality) | Kept | Yes (2-3 marks) |
| Solubility of solids in liquids | Kept | Yes (theory short answer) |
| Henry's law and applications | Kept | Yes (very frequent) |
| Raoult's law and ideal solutions | Kept | Yes (5-marker numerical) |
| Azeotropes (minimum and maximum boiling) | Kept | Yes (2-mark theory) |
| Four colligative properties | Kept | Yes (every paper) |
| Van't Hoff factor, association, dissociation | Kept | Yes (3-mark numerical) |
| Solubility of gases in liquids: detailed effect of temperature and pressure on aquatic life | Trimmed | Rare (1-mark application) |
| Reverse osmosis (extended treatment, desalination case study) | Trimmed | Brief mention only |
No major topic was fully removed from this chapter in the 2026-27 edition. Students preparing from old guidebooks can use them safely for Chapter 1, but should ignore the long aquatic-life and desalination case studies. The eight "Kept" rows above account for roughly 95% of the marks asked in CBSE Boards 2021 to 2025.
Solutions Recent Previous Year Question Pattern (2026 → 2024)
A quick three-year snapshot of how CBSE Board, JEE Main, and NEET have phrased Chapter 1 questions recently. The full year-wise map (2021 to 2026 across all three exams) is the canonical asset of the dedicated NCERT Solutions page.
| Year | CBSE Board | JEE Main | NEET |
|---|---|---|---|
| 2026 | Colligative properties (5-marker) | Henry's law, Van't Hoff factor | Pending (exam rescheduled) |
| 2025 | Raoult's law deviation (3-marker) | Osmotic pressure, molarity | Depression of freezing point, dissociation |
| 2024 | Van't Hoff factor numerical (3-marker) | Mole fraction, Henry's law | Boiling-point elevation |
Full year-wise PYQ map: Solutions Class 12 Chemistry NCERT Solutions
Related Links:
Solutions Three-Day Study Plan for This PDF
The chapter splits cleanly across three short sessions of roughly one hour each. The split below is built around the difficulty of each section: Day 1 is light theory, Day 2 is the formula-heavy core, Day 3 is exercise drill.
- Day 1 (60 minutes): Sections 1.1, 1.2, 1.3 — types of solutions, concentration expressions, solubility, Henry's law. Solve Examples 1.1 to 1.4.
- Day 2 (90 minutes): Sections 1.4, 1.5, 1.6, 1.7 — Raoult's law, ideal vs non-ideal solutions, four colligative properties, abnormal molar masses. Solve Examples 1.5 to 1.9. This is the heaviest day; bias it earlier in the week.
- Day 3 (75 minutes): Attempt all 41 back-exercise questions. Mark unsolved ones with a sticky tab; return to them after revising the relevant section.
Solutions Weightage Compared Across Class 12 Chemistry Chapters
The visual below maps the typical CBSE Board marks distribution across all 10 chapters of the rationalised 2026-27 NCERT Class 12 Chemistry book, averaged over the last five board papers. Chapter 1 Solutions, highlighted in orange, sits at the top of the Physical Chemistry block.
Chapter 1 Solutions ties with Chapter 5 Coordination Compounds for the highest CBSE board weightage in the current 2026-27 syllabus. A strong Chapter 1 score offsets any slippage in the relatively lighter chapters at the bottom of the table.
More Solutions Chemistry Class 12 Resources
NCERT Book PDF for Class 12 Chemistry: All Chapters
Use the table below to jump to the official NCERT Book PDF page for any other Class 12 Chemistry chapter. Each link opens the full chapter PDF along with its section map and rationalisation note.
| Chapter | Resource |
|---|---|
| Chapter 2 | Electrochemistry NCERT Book PDF |
| Chapter 3 | Chemical Kinetics NCERT Book PDF |
| Chapter 4 | The d- and f-Block Elements NCERT Book PDF |
| Chapter 5 | Coordination Compounds NCERT Book PDF |
| Chapter 6 | Haloalkanes and Haloarenes NCERT Book PDF |
| Chapter 7 | Alcohols, Phenols and Ethers NCERT Book PDF |
| Chapter 8 | Aldehydes, Ketones and Carboxylic Acids NCERT Book PDF |
| Chapter 9 | Amines NCERT Book PDF |
| Chapter 10 | Biomolecules NCERT Book PDF |
Solutions Class 12 Chemistry NCERT Book PDF FAQs
Ques. Where can I download the Solutions Class 12 Chemistry NCERT Book PDF?
Ans. You can download the Class 12 Chemistry Chapter 1 Solutions NCERT Book PDF directly from this page. Both the Normal and HD versions are available, and both are free. The file is the official chapter print sourced from the ncert.nic.in archive.
Ques. Is the Class 12 Chemistry Chapter 1 PDF on this page aligned with the 2026-27 NCERT?
Ans. Yes. This page reflects the current 2026-27 syllabus for Class 12 Chemistry. The new edition keeps every core sub-topic of the chapter (Henry's law, Raoult's law, all four colligative properties, Van't Hoff factor) and only trims the extended aquatic-life and desalination case studies. See the kept-trimmed-removed table above for the full audit.
Ques. How many pages is the Class 12th Chemistry Solutions NCERT Book chapter PDF?
Ans. The official NCERT chapter PDF runs 33 pages. It covers nine numbered sections (1.1 through 1.7 plus Summary and Exercises), 9 intext worked examples, and 41 back-exercise questions.
Ques. How many chapters are in the Class 12 Chemistry NCERT Book for 2026-27?
Ans. The current edition has 10 chapters in total, with Solutions as Chapter 1. The older "Polymers", "Chemistry in Everyday Life", "Surface Chemistry", "p-Block Elements", and "General Principles and Processes of Isolation of Elements" units were dropped during the rationalisation.
Ques. What is the CBSE board exam weightage of Class 12 Chemistry Chapter 1 Solutions?
Ans. Chapter 1 Solutions carries 6 to 8 marks in the CBSE Class 12 Chemistry Board exam, typically split as one 5-mark long-answer question on colligative properties plus one or two short-answer or MCQ items from Henry's law, Raoult's law, or Van't Hoff factor.
Ques. Which section of Class 12 Chemistry Chapter 1 is the most important for JEE Main and NEET?
Ans. Section 1.6 Colligative Properties is the heaviest source of both JEE Main and NEET questions, followed by Section 1.4 Vapour Pressure (Raoult's law) and Section 1.7 Abnormal Molar Masses (Van't Hoff factor). Roughly 4 to 5% of every JEE Main shift includes a Solutions question, and NEET prints 2 to 3 questions per paper from these three sections combined.
Ques. Should I read this chapter linearly or jump to specific sections?
Ans. A three-pass read works best (Skim, Deep with examples, Exercise drill). Sections 1.1 to 1.3 are light theory and can be read in any order; Sections 1.4 to 1.7 build on each other, so read them in sequence. Use the three-day plan above to allocate time.
Ques. Is the Collegedunia version of this PDF different from the official NCERT PDF?
Ans. The PDF file itself is the official NCERT print, unchanged. What Collegedunia adds on this page is the section-by-section map with page numbers, the intext example inventory, the 2026-27 rationalisation audit, the three-day study plan, and cross-links to the matching Notes, Solutions, and Formula Sheet pages.
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