Test: Adsorption (Old NCERT) - NEET MCQ

Sorption

Desorption

Physisorption

Chemisorption

In adsorption, the substance is concentrated only at the surface while in absorption it is uniformaly distributed in the bulk

Adsorption is instantaneous while absorption is a slow process

A substance can be adsorbed as well as absorbed simultaneously and the process is called sorption

Only gases are adsorbed while solids and liquids are absorbed

Adsorption is an exothermic process

They become inert and do not react with the adsorbate

The extent of adsorption increases with increase in surface area of the adsorbent

Adsorption is more if the size of adsorbent is small

Adsorbing power is increased by increasing surface area by making the surface rough

Adsorbing power is increased by dipping the surface in acid to make it smooth

Adsorbing power is increased by dissolving it in water

Adsorbing power is decreased to reduce the extent of adsorption

ΔG

ΔS

ΔH

All of these

High specificity

Irreversibility

Non-specificity 

None of these

It is a reversible process

It requires less heat of adsorption

It requires activation energy

It takes place at low temperature

It lacks specificity

It is generally reversible

Porous surfaces are good adsorbent 

Heat of adsorption is quite high

High temperature, low pressure

High temperature, high pressure 

Low temperature, low pressure

Low temperature, high pressure

Increase with decrease in temperature 

Increase with increase in temperature

Decrease with decrease in temperature

Decrease with increase in temperature

HCl

NH₃

O₂

CO₂

Adsorption is specific

Heat of adsorption is of the order of 200 kJ mol^-1

Adsorption is irreversible

Adsorption may be multimolecular layers

Chemical adsorption

Positive adsorption

Activated adsorption

Passive adsorption

On increasing pressure, adsorption keeps on increasing

Enthalpy and entropy changes are negative

Chemisorption is more specific than physisorption

It is a reversible reaction

Physical adsorption occurs at a low temperature and chemisorption occurs at all temperatures

Magnitude of chemisorption decreases with rise in temperature while physisorption increases with rise in temperature

Chemisorption is irreversible and physisorption is reversible

In physisorption activation energy is low while in chemisorption it is high

Directly proportional to the pressure of gas

Inversely proportional to the pressure of the gas

Independent of the pressure of the gas

Proportional to the square of the pressure of the gas

Always greater than one

Always smaller

Always equal to one

Greater than one at low temperature and smaller than one at high temperature

x/m vs p

log x/m vs p

x/m vs log p 

log x/m vs log p

The figure shows Freundlich adsorption isotherm

The figure shows Langmuir adsorption isotherm

The adsorption varies directly with pressure

The factor 1/n can have values between 0 and 1

Zero-order kinetics

First order kinetics

Second order kinetics

Fractional order kinetics

It acts as an adsorbent for poisonous gases present in coal mines

It acts as an adsorbent for coal particles present in coal mines

It acts as a mask through which exhaled gases are diffused out

It acts as a base for scattering the light

H₂

O₃

N₂

SO₂

 (A) → (i), (B) → (iii), (C) → (ii), (D) → (iv)

(A) → (ii), (B) → (iii), (C) → (i), (D) → (iv)

(A) → (iii), (B) → (i), (C) → (iv), (D) → (ii)

(A) → (iv), (B) → (i), (C) → (iii), (D) → (ii)

Adsorption indicators 

Thin layer chromatography 

Qualitative analysis

All of these