Tag: surface chemistry

Questions Related to surface chemistry

Application of adsorption in pharmacy and allied field is/are :

applications of adsorption adsorption adsorption and colloids surface chemistry chemistry

  1. Decolourising agents

  2. Adsorption chromatography

  3. Purified talc

  4. None of the above

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Correct Option: A,B
Explanation:

Application of adsorption in pharmacy and allied fields are Decolourising agents, adsorption chromatography.

Application of adsorption in food industry is/are :

applications of adsorption adsorption adsorption and colloids surface chemistry chemistry

  1. decolourisation of edible oils

  2. to remove bitter substances from fruit juices

  3. to remove salt from water

  4. to remove sugar contents

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Correct Option: A,B
Explanation:

Decolorization of edible oils and removing bitter substances can be obtained through adsorption.

The ion exchange resins helps in:

applications of adsorption adsorption adsorption and colloids surface chemistry chemistry

  1. Removing moisture

  2. Controlling humidity

  3. Removing hardness of water

  4. All of the above

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Correct Option: C
Explanation:

Ion exchange resin method is used for removing hardness of water.

Application of adsorption chromatography is/are _________.

applications of adsorption adsorption adsorption and colloids surface chemistry chemistry

  1. separation of relatively non polar, water insoluble compounds

  2. seperation of isomers

  3. purification of antibody fragments

  4. all of the above

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Correct Option: D
Explanation:

Adsorption chromatography has many applications. Generally, it is used for determining the concentration of a compound (or its purity), separating out a mixture into individual componentsseperation of isomers, and identifying what is in a mixture and seperate on the basis of solubility also. There are three main types of adsorption chromatography - column, thin layer, and gas-solid.

Adsorption column chromatography has been used for :

applications of adsorption adsorption adsorption and colloids surface chemistry chemistry

  1. isolation and purification of vitamins and hormones

  2. examination of vegetable oil and pharmaceutical preparations

  3. used as indicator

  4. all of the above

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Correct Option: A,B
Explanation:

Column chromatography is used for isolation and purification of vitamins and hormones and for the examination of vegetable oil and pharmaceutical preparations.

Which of the following is most favourable for vander waals  adsorption?

applications of adsorption adsorption adsorption and colloids surface chemistry chemistry

  1. high pressure and high temperature

  2. low pressure and low temperature

  3. low pressure and high temperature

  4. high pressure and low temperature

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Correct Option: D
Explanation:

Physisorption is Vanderwaals adsorption, it occurs at high pressure and low temperature conditions.

What does a catalyst do?

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

  1. Alter the state of equilibrium.

  2. Decreases the activation energy.

  3. Increases collision frequency.

  4. Increases the average kinetic energy of reacting species.

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Correct Option: B
Explanation:

Catalyst is a substance, which lowers the activation energy of reaction because it provides an alternate pathway for reaction. Also, it increases backward and forward reaction to the same extent. Due to this lower activation energy, equilibrium is attained faster.

Which of the following are electrophiles?

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

  1. $BF _3$

  2. $: CCl _2$

  3. $^{\oplus}NH _4$

  4. $I^{\ominus}$

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Correct Option: C

Which of the following is the best way to speed up a chemical reaction?

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

  1. Make an effort to concentrate the reactants as best as possible

  2. Add a catalyst

  3. Cool the reaction down

  4. Increase the pressure on the system

Show answer
Correct Option: B
Explanation:
5 ways to increase the reaction rate :
1. The nature of the reactants: A reaction between two gases would be faster than a reaction between to liquids or two solids.
2. Temperature:  The heat causes the particles to move quickly, and due to the Collision Theory,  the reaction will occur faster.
3. Concentration: The higher the concentration of a reactant, the quicker the reaction will occur. 
4. Surface Area: The more the particles are exposed, the faster it is for the other reactant to collide into the particles, meaning the reaction rate will increase.
5. Catalysts: Catalysts are substances that increase the rate of reaction by speeding up the reaction without being used up in the reaction.
Adding catalyst can most effectively speed up the chemical reaction. 

Competitive inhibition is reversible.

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

  1. True

  2. False

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Correct Option: A
Explanation:

Competitive Inhibitors belong to the category of enzymes known as reversible inhibitors. Reversible inhibitors dissociate the enzyme-inhibitor complex as soon as possible.

This Chemical reaction can be reversed by increasing concentration of substrate. These process continuously takes place as $E + S \rightarrow ES \rightarrow E + P$