According to the adsorption theory of catalysis the speed of

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 Multiple Choice QuestionsMultiple Choice Questions

61.

Colloidal solution of gold is in different colours like red, purple, blue and golden because of

  • variable oxidation states of gold

  • size difference in the particles of gold

  • presence of impurities

  • difference in the concentration of gold particles


62.

The size of colloidal particles is in between

  • 10-7 - 10-9 cm

  • 10-9 - 10-11 cm

  • 10-5 - 10-7 cm

  • 10-2 - 10-3 cm


63.

The stability of lyophilic colloids is due to which of the following?

  • Charge on their particles

  • Large size of their particles

  • Smaller size of their particles

  • A layer of medium of dispersion on their particles


64.

Milk is

  • fat dispersed in water

  • water dispersed in fat

  • water dispersed in oil

  • fat dispersed in fat


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65.

In chemical adsorption, how many layers are adsorbed?

  • One

  • Two

  • Multi

  • Zero


66.

What is the role of a catalyst in a catalysed reaction?

  • Lowers the activation energy

  • Increases the activation energy

  • Affects the free energy change

  • Affects the enthalpy change


67.

For coagulating As2S3 colloidal solution which of the following will have the lowest coagulation value?

  • NaCl

  • KCl

  • BaCl2

  • AlCl3


68.

Which of the following chemical reactions is homogeneous catalytic reaction?

  • N2(g) + 3H2(g) Fe 2NH3(g)

  • 2SO2(g) + O2(g) NO 2SO3 (g)

  • CO(g) + 3H2(g) Ni CH4(g) + H2O (g)

  • 2SO2(g) + O2(g) V2O5 2SO3(g)


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69.

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

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

  • in the process of adsorption, the activation energy of the molecules becomes large

  • absorption produces heat which increases the speed of the reaction

  • adsorption lowers the activation energy of the reaction


A.

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

The reactant gaseous molecules are adsorbed on the surface by these free bonds. This accelerates the rate of the reaction. The distribution of free bonds on the catalyst surface is not uniform. These are crowded at the 'peaks', 'cracks' and comers of the catalyst. The catalytic activity due to adsorption of reacting molecules is maximum at these spots. These are, therefore, referred to as the active centres.


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70.

Which of the following will have the highest coagulating power for As2S3 colloid?

  • PO43-

  • SO42-

  • Al3+

  • Na+


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