Surface Chemistry

Surface ChemistryNEET Chemistry · Class 12 · NCERT Chapter 14

Overview Notes NEET Questions Interactive Learning

2 interactive concept widgets for Surface Chemistry. Drag any slider, change any number, and watch the formula and the answer update live. Built so you understand how each NEET problem actually works, not just the final number.

On this page

Adsorption simulator: physisorption vs chemisorption with temperature slider, Freundlich and Langmuir graphs, and NEET key facts

Colloid identifier: dispersed phase x dispersion medium → type name, examples, stability, Hardy-Schulze quick reference

Adsorption graph simulator

Select physisorption or chemisorption, then slide the temperature. See how adsorption extent (x/m) changes with temperature for each type. Compares Freundlich and Langmuir isotherms side by side with labeled graphs.

Adsorption Graph Simulator

Select physisorption or chemisorption, then adjust the temperature slider. See how adsorption extent (x/m) changes with temperature for each type. Compare the graphs and review the NEET-key equations and properties.

Select Adsorption Type

Temperature Control

Temperature: Room (25°C)

Adsorption extent (x/m) at selected temperature

65%

Physisorption ←

55%

Chemisorption

Physisorption at Room (25°C)High adsorption at low temperature (exothermic favoured)

Physisorption Properties

NEET

Force of attractionWeak van der Waals forces

Enthalpy of adsorption20-40 kJ/mol (low)

ReversibilityReversible (reduce pressure or heat slightly)

Layers formedMultilayer adsorption

Activation energyNo activation energy needed

SpecificityNot specific (any gas on any surface)

ExampleN2 or CO2 adsorbed on charcoal or mica at low temperature

Adsorption Isotherm Graphs

Freundlich Isotherm: log(x/m) vs log P

Langmuir Isotherm: x/m vs P (monolayer saturation)

At high P: x/m approaches constant maximum ‘a’ (all surface sites filled). At low P: x/m is linear with P. Key advantage over Freundlich: built-in saturation.

NEET Exam Notes

Freundlich equation: x/m = kP^(1/n). Log form: slope = 1/n, intercept = log k. This graph question appears every 2-3 years.
Physisorption: van der Waals, 20-40 kJ/mol, reversible, multilayer, decreases with T.
Chemisorption: chemical bonds, 40-400 kJ/mol, irreversible, monolayer, first increases then decreases with T.
Langmuir isotherm: monolayer, all sites equivalent, saturation at high pressure.
Adsorption is always exothermic (delta H is negative).

Colloid type identifier

Pick dispersed phase (solid/liquid/gas) and dispersion medium (solid/liquid/gas) to identify the colloid name, examples, lyophilic/lyophobic character, and NEET frequency. Includes a clickable list of 7 important NEET colloids (As2S3, Fe(OH)3, gold sol, starch, micelles, milk, butter) with charge and key facts.

Colloid Type Identifier

Select the dispersed phase and dispersion medium to identify the colloid type, see real-life examples, stability, and NEET frequency. Then explore the important individual colloids tested in NEET with their charge, character, and key facts.

Select Phases

Dispersed Phase (the minor component)

Dispersion Medium (the major component)