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Surface chemistry III
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Catalysts and catalysis

Shaillee Kaushal is teaching live on Unacademy Plus

Shaillee Kaushal
Faculty in Chemistry with a teaching experience of 14 years. Specialised in teaching for boards and competitions.

U
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Gud Evening Bhaiya.. Bhaiya unacdmy se vedio dekhne me bht dikkat hoti ha aise me downliad ho ni pata aur fone p hi dekhna padta ha aise me youtuve se tubemete se vedio downpiad krke aram se pause krkrke pura likh bhi lete h notes tayyar ho jati ha aap please youtube p upload kr diya kariye please ya fr aap apne channel p news and editorial kiya kariye bhaiya please humble request hai..
Jatin Verma
2 years ago
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Rahul Tripathi
2 years ago
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Sunny O
2 years ago
Kahan seho Tripathi ji?
Neetu mehmi
2 years ago
How to download video from you tube
Sunny O
2 years ago
Neetu if you are tech savvy ...You can download 1click youtube downloader for mozilla firefox browser and you can download any video in any format by single click a button down to every youtube video screen.
Neetu mehmi
2 years ago
Oh thanks
Ashish Kashyap
2 years ago
Follow these steps to download unacademy videos. Step 1: Open Unacademy Learning App and go to your profile. Step 2: Select the course and watch any one lesson of that and then click to download all
Neetu mehmi
2 years ago
Thanks
Swati Singh
2 years ago
Triparthi ji apne kitna cute likha hai :)
Rahul Tripathi
2 years ago
Thank you Swati Ji waise cute kya likha ha Jatin bhaiya k lie bht respect ha he is doing great Job to aise logo k lie hmesha dill se respect khud ajati hai..
Rahul Tripathi
2 years ago
Aur Sunny Ji hm UP se hain Allahabad se..
Swati Singh
2 years ago
well said :)
Sunny O
2 years ago
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Rahul Tripathi
2 years ago
Strange ni Sunny Ji mere bhi gav ha jata bhi rahta hu waha 3mbps hi speed rahti ha.. Sunny ji apko bata de ki hota kya ha network traffic ek hota ha jaise jaha jitta jada usage waha data utna slow hojata ha gav me har kisi k hath me mob ni hota ha bt urban me har koi kaan me headfone lga k mob hi me laga dikhega chahe youtube ho ya koi bhi social site aur chalta mere yaha bhi acha ha bt subah 4 bje hm uthte bhi ha 5 bje aur uth k pahle kaam yai hta ha ki hmne kayi channel education k subscribe kiye rakhe ha Study Iq, aur ek do ha to sbke jo bhi kaam k vedios hote ha trnt download me lga dete ha kyuki after 9 am net ki speed slow hojati ha hm Salori me rahte ha University Of Alld nd this area is Densly populated with students yaha jb Mob hote ha na to special force ati ha in order to cintroll that to aap guess lga lo jbki tower of Jio is just a mile away from my home..
Sunny O
2 years ago
Han han ji bilkul... Jio fenko Airtel Voda try kro unme etni buri situation nahi,,, just try it ...or jyda charge bhi nahi rahe ab,, 348 me daily 1gb + call sms free. Jio ke pas channels limited h jo subscriber using bdhne pr slow ho jate h
Rahul Tripathi
2 years ago
Ha airtel bhi ha chaliye abki ye khtm hoga to next recharge airtel me hi hoga sir..
Ritesh Tiwari
2 years ago
हां जी सर, कृपया ये सुनिश्चित कीजिए कि वीडियो यट्यूब पर समय पर अपलोड हो जाए।
Mahesh Tripathi
2 years ago
Gazab hi chaye ho Rahul Tripathi ji... Kuch to laz rakhe raho bhai Allahabad ki itna bhi samasya nahi hai jitna aap darsana chahate hai
  1. XII -05 SURFACE CHEMISTRY -11I


  2. Adsorption form solution phase:- Solids can adsorb solutes from solutions also When a solution of acetic acid in water is shaken with charcoal, a part of the ac adsorbed by the charcoal and the concentration of the acid decreases in the solution The following observations have been made in the case of adsorption from solution phase: (i) The extent of adsorption decreases with the increase of temperature (ii) The extent of adsorption increases with the increase of surface area of the adsorbent (ili) The extent of adsorption depends on the concentration of the solute in solution (iv) The extent of adsorption depends upon the nature of the adsorbent and the adsorbate The extent of adsorption xkC1/ On taking log on both sides: log = logk + log c m n


  3. Adsorption Isobars and isostere A graph between degree of adsorption (n/m) and temperature '' at a constant pressure of adsorbate gas is known as adsorption isobar. P constart P constart E 2


  4. Adsorption Isostere: Degree of adsorption depends on temperature as well as an pressure. When temperature increases, the extent of adsorptio decreases. >The plot of temperature versus pressure for a give amount of adsorption is called adsorption isostere.


  5. Application of Adsorption: 1. Production of high vaccunm 2. Gas masks: 3. Humidity control: 4. Removal of colouring matter from solution 5. Heterogenous catalysis: 6. Separation of inert gases: Apart from the above applications adsorption is also used in the following: (i) In curing diseases (ii) Cleaning agents (ii) Froth floatation process (iv) Chromatographic analysis, (v) kinetics


  6. Catalysis The rates of a number of reactions can be altered by adding a foreign substances. The systematic study of the effect of various foreign substance on the rates of reaction has studied by Berzilius. Such substances are called catalysts. They are defined as substances which changes the reaction rates withou affecting the overall energies of the reaction. > The phenomenon of altering the rate of a reaction by catalysts are called catalysis.


  7. Types of Catalysis: 1. Homogenous Catalysis: When the reactants, products and catalysts are all in the same phase, the catalysis is said to b homogenous For example: NO(g) 2S02(g) + 02(g) 2S03 (g) CH3C0OCH3(1) + H20() CH3COOH) + CH30H) CH30H) HCI(I) 2. Heterogenous catalysis: The catalytic process in which the reactant, catalysts and products are in the differ heterogeneous catalysis: For. eg: Pt(s) 2502(g) + O2(g)--2S03(g) N2O + 3H2(g) 2NH3(g) 4NH3 (g) + SO2(g)- 4N0(g) + 6H2O(g) Pt(s)


  8. Types of catalysis:- 1. Positive Catlalysis: When the rate of reaction is accelerated by the foreign substance is said to be a positive catalyst and the phenomenon as positive cafalysis Example Pt 2H202 2H20 + 02 2KC Og 2KCI + 302 2S02 + 02 2S03 Positive catalyst increase the rate by lowering activation energy of reaction. 2700C V205 Catalyst changes the mechanism by changing the intermediate i.e on intermediate of low energy is formed.


  9. 2. Negative Catalysis: There are certain substances which when added to the reaction mixture retard the reaction rate instead of increasing it. These are called negative catalysts or inhibitors and the phenomenon is called negative catalyst Examples: (i) The oxidation of Na2SO3 by air is retarded by alcohol. (ii) The oxidation of benzaldehyde is retarded if some diphenyl amine is added. Alchol 2c,HsCHO+2ipheny asCOOH


  10. 3. Autocatalysis: In certain reactions, one of the product act as catalyst. Initially the reaction is slow but as soon as the products are formed, the reaction rate increases due to the action of one of the produet as catalyst. This phenomenon is called autocatalysis. Examples of Autocatalysis: > The rate of oxidation of oxalic acid by acidified potassium permanganat increases on the reaction progresses. This is due to presence of Mn2+ ions act as auto catalyst 5H2 C204 2KMnO4 +3H2SO42MnSO4 + K2S04 + 10C02 + 8H20 When nitric acid is poured on copper, the reaction is very slow in the beginning gradually the reaction becomes faster due to formation of ions during the reaction which acts as an auto catalyst