Surface Chemistry
Adsorption, catalysis, colloids and emulsions
Key Concepts
- Adsorption: accumulation of substance on surface (adsorbate on adsorbent)
- Physisorption: weak van der Waals forces; chemisorption: chemical bonds
- Colloids: dispersed particles 1–1000 nm in size; show Tyndall effect
- Coagulation: colloidal particles aggregate and settle
- Catalysis: catalyst provides alternative pathway with lower activation energy
Important Formulae
| Freundlich adsorption isotherm | x/m = kP^(1/n), n ≥ 1 |
| Langmuir adsorption isotherm | x/m = abP / (1 + bP) |
Quick Tips
- Physisorption increases at low T; chemisorption increases at high T (up to a limit).
- Sols: solid dispersed in liquid; gels: liquid dispersed in solid; emulsion: liquid in liquid.
- Hardy-Schulze rule: higher valency of coagulating ion → more effective coagulation.
Sample Practice Questions
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Peptisation means:
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Answer: Converting precipitate back to colloidal state by adding electrolyte
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Lyophilic colloids (e.g. gelatin in water) are:
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Answer: Stable and reversible
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Chemisorption is:
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Answer: Irreversible and involves chemical bond formation
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Tyndall effect is the scattering of light by:
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Answer: Colloidal particles
Practice Questions
Practice 20 randomly selected NEET questions on Surface Chemistry. Answers are revealed after each question.
Start Practice →Frequently Asked Questions
What are the key concepts in Surface Chemistry for NEET?
Adsorption: accumulation of substance on surface (adsorbate on adsorbent); Physisorption: weak van der Waals forces; chemisorption: chemical bonds; Colloids: dispersed particles 1–1000 nm in size; show Tyndall effect; Coagulation: colloidal particles aggregate and settle; Catalysis: catalyst provides alternative pathway with lower activation energy.
Which formulae are important for Surface Chemistry in NEET?
Freundlich adsorption isotherm: x/m = kP^(1/n), n ≥ 1; Langmuir adsorption isotherm: x/m = abP / (1 + bP).
How can I practise NEET Surface Chemistry questions for free?
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