Tag: adsorption theory of heterogeneous catalysis

Questions Related to adsorption theory of heterogeneous catalysis

In a chemical reaction, the solid catalyst function as:

chemistry adsorption and colloids adsorption theory of heterogeneous catalysis enzymes and catalysts catalysis

  1. Adsorbent

  2. Adsorbate

  3. Micelle

  4. None of the above

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Correct Option: B

Removal of adsorbate from the surface of adsorbent is called _____.

chemistry adsorption and colloids adsorption theory of heterogeneous catalysis enzymes and catalysts catalysis

  1. desorption

  2. absorbation

  3. adsorbation

  4. none

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Correct Option: A
Explanation:

Removal of adsorbate from the surface of adsorbent is called desorption.
It is the reverse of adsorption. 

For example, when hydrogen gas is adsorbed on the surface of Pt and the temperature is raised or pressure is lowered, some of the hydrogen gas escapes from the surface of Pt. This is known as desorption.

The name catalysis was given by: 

chemistry adsorption and colloids adsorption theory of heterogeneous catalysis enzymes and catalysts catalysis

  1. Rutherford

  2. Langmuir

  3. Graham

  4. Berzelius

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Correct Option: D
Explanation:

The word catalysis was first used by Berzelius in 1836 to describe a number of experimental reactions. Catalysis is defined as a phenomenon in which the presence of a foreign compound in a reaction can accelerate its rate without being used  in that reaction. These foreign substances are called as a catalyst.

According to adsorption theory of catalysis, the reaction rate increases, because:

chemistry adsorption and colloids adsorption theory of heterogeneous catalysis enzymes and catalysts catalysis

  1. Adsorption produces heat which increases the rate of reaction

  2. In the process of adsorption, the kinetic energy of the molecules increases

  3. The concentration of reactants at the active centres becomes high due to adsorption

  4. The activation energy of the reaction becomes high due to adsorption

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Correct Option: C

In which of the following processes, a catalyst is not used? 

chemistry adsorption and colloids adsorption theory of heterogeneous catalysis enzymes and catalysts catalysis

  1. Haber's process and Deacon's process

  2. Deacon's process and Solvay process

  3. Solvay process and Lead chamber process

  4. None of these can proceed without catalyst

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Correct Option: D
Explanation:

Haber's process catalyst is finely divided iron

Deacon's process catalyst is copper chloride

Solvay process catalyst is ammonia-soda

Lead chamber process catalyst is platimnum.

So in the all above process is catalyst is used.

According to adsorption theory of catalysis, the speed of reaction increases because:

chemistry adsorption and colloids adsorption theory of heterogeneous catalysis enzymes and catalysts catalysis

  1. the concentration of the reactant molecules at the active centres of the catalyst becomes high due to adsorption

  2. in the process of adsorption, the activation energy of the molecules becomes large

  3. adsorption produces heat which increases the speed of the reaction

  4. adsorption lowers the activation energy of the reaction

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Correct Option: A
Explanation:

According to adsorption theory of catalysis, the speed of reaction increases because the concentration of the reactant molecules at the active centres of catalyst becomes high due to adsorption.

Hence option A is correct.

According to the adsorption theory of catalysis,the speed of the reaction increase because :

chemistry adsorption and colloids adsorption theory of heterogeneous catalysis enzymes and catalysts catalysis

  1. The concentration of reactant molecules at the active centers of the catalyst becomes high due to adsorption

  2. In the process of adsorption, the activation energy of the molecules becomes large

  3. Adsorption produces heat which increases the speed of the reaction

  4. Adsorption lowers the activation energy of the reaction.

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Correct Option: D
Explanation:

The correct answer is $D$ . In the presence of catalyst the speed of reaction increases since the activation energy gets reduced and hence the rate of adsorption increases.

Chlorophyll, the green colouring matter in plants helps the process of photosynthesis by:

chemistry adsorption and colloids adsorption theory of heterogeneous catalysis enzymes and catalysts catalysis

  1. acting as a catalyst

  2. converting soil into carbohydrates

  3. reacting with carbon dioxide

  4. fixing soil nitrogen

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Correct Option: A
Explanation:
Chlorophyll plays a vital role by absorbing sunlight of a range of wavelengths, primarily blue and red. It is a catalyst for photosynthesis - increasing the speed of the reaction by taking part in it but remaining unchanged at the end.

Match the reaction of Column - I with the catalysts in Column - II:

Column - I(Reaction) Column - II(Catalyst)
(a) $2KClO _3(s) \rightarrow 2KCl(s) +3O _2(g)$ (p) $Al _2O _3$
(b) $ 2SO _2(g) +O _2(g) \rightarrow 2SO _3(g)$ (q) $Pt$
(c) $2H _2O _2(l) \rightarrow 2H _2O(l) +O _2(g)$ (r) $V _2O _5$
(d) $ N _2(g) + 3H _2 (g) \rightarrow 2NH _3 (g)$ (s) $MnO _2$
chemistry adsorption and colloids adsorption theory of heterogeneous catalysis enzymes and catalysts catalysis

  1. $a\rightarrow s,b\rightarrow r,c\rightarrow s,d\rightarrow p\ & \ q$

  2. $a\rightarrow p,b\rightarrow r,c\rightarrow s,d\rightarrow p\ & \ s$

  3. $a\rightarrow q,b\rightarrow r,c\rightarrow s,d\rightarrow q$

  4. $a\rightarrow s,b\rightarrow r,c\rightarrow q,d\rightarrow p\ & \ q$

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Correct Option: A
Explanation:

a)  For $KClO _3$ decomposition Manganeese(IV) oxide is used as catalyst at an elevated temparature of 150 degree given by the formula $MnO _2$.


b) The catalyst that promotes the $SO _2$ oxidation at temparature of 500 degree where $SO _2$ is thermodynamically efficient is vanadium pentoxide given by $V _2O _5$.


c) The catalyst that provides alternative way with low activation energy  for decomposition of $H _2O _2$ is $MnO _2$.

d) Synthesis of Ammonia by Haber process uses $Pt$ and $Al _2O _3$ as a compromise catalysts in place of $Fe$.

Option A is correctt.