Intermolecular Force – Complete Notes, Revision, Important Questions & Downloads
This opening topic defines the two interactions that the rest of the chapter keeps using: Cohesive Force and Adhesive Force. NEET tests this section through direct statements and examples such as why mercury forms globules, why water wets glass, or whether attraction is between similar or different substances. The OCR page is short but foundational because surface tension, capillarity, and wetting all depend on the balance between these two forces. If cohesion and adhesion are fixed clearly now, later examples stop looking unrelated.
NEET Weightage - Intermolecular Force
Surface Tension| NEET Year | Questions from this Topic | Bar | Marks |
|---|---|---|---|
| NEET 2024 | 0 | 0 | |
| NEET 2023 | 0 | 0 | |
| NEET 2022 | 0 | 0 | |
| NEET 2021 | 0 | 0 | |
| NEET 2020 | 0 | 0 | |
| NEET 2019 | 0 | 0 | |
| Total (2019-2024) | 0 | 0 |
Cohesion means same-substance attraction, while adhesion means attraction between different substances.
The OCR adds that these forces vary inversely as the eighth power of intermolecular distance.
Most later wetting and globule examples reduce to comparing cohesion and adhesion correctly.
Intermolecular Force Strategy for NEET
Use the substances, not the story Ignore whether the example is about sticking, spreading, or beading. Ask only whether the attraction is between like molecules or unlike molecules.
Anchor one example for each force Mercury droplets staying together is cohesion; water wetting glass is adhesion. These two examples can reconstruct most others.
Remember the distance rule qualitatively The eighth-power dependence means these forces change rapidly with separation, which helps explain why molecular effects are short-ranged.
Connect this topic forward Surface tension later relies on net cohesive attraction at the free surface, so keep cohesion especially clear.
Intermolecular Force Study Materials
PDF · Cheat Sheet · MCQ Set · PYQIntermolecular Force Subtopics
2-Column Table| Column A | Column B |
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Rapid Revision - Intermolecular Force
Concept → Trap → Example1) Cohesive Force
Same substanceCohesive force is the attraction between molecules of the same substance. In liquids it is weaker than in solids and in gases it is still weaker.
- It explains why drops of the same liquid merge into one larger drop.
- Strong cohesion in mercury helps it form globules instead of spreading readily.
- Surface tension later in the chapter is mainly a consequence of cohesive attraction at the free surface.
2) Adhesive Force
Different substancesAdhesive force is the attraction between molecules of different substances. It governs wetting, sticking, and spreading at interfaces of unlike materials.
- Water wets glass when attraction between water and glass is sufficiently strong.
- Gum sticking paper sheets together is an adhesion example.
- Comparing adhesion with cohesion explains many capillarity and wetting outcomes later.
US Curriculum Gaps - Intermolecular Force
What U.S. Students Usually MissThe exam asks same-substance versus different-substance attraction explicitly
Many learners remember the words but fail on examples. NEET questions are often solved by checking whether the molecules involved are identical or different.
- Cohesion = same substance.
- Adhesion = different substances.
Wetting and globule formation come from force comparison
Students may memorise examples separately. The chapter expects them to be read through competition between cohesion and adhesion.
- Mercury globule points to strong cohesion.
- Water on glass points to adhesion.
Concept IQ Check - Intermolecular Force
4 NEET-style MCQs with AnswersPractice Questions - Intermolecular Force
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NEET Physics Revision Checklist
Use this section for quick chapter tracking before mocks, part tests, and final NEET revision.
Intermolecular Force FAQs
Notes · Downloads · Revision · Important QuestionsWhy is cohesion important for surface tension?
Why is adhesion important for wetting?
What is the easiest way to distinguish cohesion and adhesion in MCQs?
Why are these forces called intermolecular?
Does the chapter treat these forces as long-range?
Why does mercury usually not wet glass the way water does?
Why is chalk writing on the blackboard listed here?
Can one example involve both cohesion and adhesion?
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