Surface Chemistry

Question 1
CBSEENCH12006411

Why are substances like platinum and palladium often used for carrying out electrolysis of aqueous solutions?

Solution

Answer:

The Plantium and palladium are used for electrolysis of aqueous solution due to the chemically inert in nature and good adsorptive capacity for hydrogen.
Because Gases like hydrogen are absorbed on the surface of platinum and palladium (adsorption) and then passes into the bulk of the adsorbent (platinum and palladium).

 
Question 2
CBSEENCH12006412

Why does physisorption decrease with the increase of temperature?

Solution
Answer:

It is because physical adsorption involves weak forces of attraction between adsorbent and adsorbent molecules, generally of Vander Waal's type. These forces decrease rapidly with increase in temperature.
Question 3
CBSEENCH12006413

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

Solution
Answer:
Powderded substance are more effective adsorbent than their crystalline forms because when a substance is powdered its surface area increase and physisorption is directly proportional to the surface area of adsorbent,
Question 4
CBSEENCH12006414

In Haber's process, hydrogen is obtained by reacting methane with steam in presence of NiO as catalyst. The process is known as steam reforming. Why is it necessary to remove CO when ammonia is obtained by Haber’s process?

Solution
Answer:

Presence of CO in the synthesis of ammonia by Haber’s process adversely affects the activity of iron catalyst.

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