NCERT solutions for Chemistry [English] Class 12 chapter 5 - Surface Chemistry [Latest edition]

Write any two characteristics of Chemisorption.

Give reasons for the following observations:

Physisorption decreases with increase in temperature.

Why are powdered substances more effective adsorbents than their crystalline forms?

It is necessary to remove CO when ammonia is prepared by Haber's process.

Why is the ester hydrolysis slow in the beginning and becomes faster after sometime?

What is the role of desorption in the process of catalysis?

What modification can you suggest in the Hardy-Schulze law?

Why is it essential to wash the precipitate with water before estimating it quantitatively?

Distinguish between the meaning of the terms adsorption and absorption. Give one example of.

What is the difference between physisorption and chemisorption?

Give reason why a finely divided substance is more effective as an adsorbent.

What are the factors which influence the adsorption of a gas on a solid?

What is an adsorption isotherm?

Describe Freundlich adsorption isotherm.

What do you understand by activation of adsorbent? How is it achieved?

What role does adsorption play in heterogeneous catalysis?

Why is adsorption always exothermic?

How are the colloidal solutions classified on the basis of physical states of the dispersed phase and dispersion medium?

Discuss the effect of pressure and temperature on the adsorption of gases on solids.

What are lyophilic and lyophobic sols? Give one example of each type. Why are hydrophobic sols easily coagulated?

What is the difference between multimolecular and macromolecular colloids? Give one example of each. How are associated colloids different from these two types of colloids?

What are enzymes? Write in brief the mechanism of enzyme catalysis.

How are colloids classified on the basis of Physical states of components

How are colloids classified on the basis of Nature of dispersion medium

How are colloids classified on the basis of  Interaction between dispersed phase and dispersion medium?

Explain what is observed When a beam of light is passed through a colloidal sol.

Explain what is observed An electrolyte, NaCl is added to hydrated ferric oxide sol.

Explain what is observed Electric current is passed through a colloidal sol?

How do emulsifires stabilise emulsion? Name two emulsifiers.

Action of soap is due to emulsification and micelle formation. Comment.

Give four examples of heterogeneous catalysis.

What do you mean by activity and selectivity of catalysts?

Describe some features of catalysis by zeolites.

What is shape selective catalysis?

Explain the term Electrophoresis

Explain the terms Coagulation

Explain the terms Dialysis 

Explain the terms Tyndall effect.

Give four uses of emulsions.

What are micelles? Give an example of a micellers system.

Explain the terms with suitable examples: - Alcosol

Explain the terms with suitable examples Aerosol 

Explain the terms with suitable examples: Hydrosol

Comment on the statement that “colloid is not a substance but a state of substance”.