CATALYSIS

How does a catalyst work in speeding up a reaction?

• by lowering the activation energy or reaction

• by giving them more energy

• by making them more available

• by increasing the activation energy or reaction

Catalysts may be in the state of ___________.

• Solid and liquid only

• Liquid and gases only

• Solid and gases only

• Solid, liquid or gases

Which of the following is incorrect for a catalyst?

• Bio-chemical reactions are mostly catalysed by enzymes

• Catalyst does not start a reaction

• Catalyst changes the equilibrium constant of a reaction

• Co-enzymes increase the activity of an enzyme

Which of the following is used as a catalyst in the haber process?

• V₂O₅

• Fe

• Ag₂O

• SO₃

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

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

• adsorption produces heat which increases the speed of the reaction

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

• adsorption lowers the activation energy of the reaction

Which one of the following is not an example for heterogenous catalysis?

• Hydrogenation of oil

• Manufacture of ammonia by Haber's process

• Manufacture of sulphuric acid by Contact process

• Hydrolysis of sucrose in presence of dilute hydrochloric acid

surface of the catalyst must be

• smooth

• evenly spread out

• cracks and peaks

• none of the above

catalytic poison in contact process

• Pt

• As₂O₃

• Fe

• H₂S

The number of active centers are increased by

• catalyst

• catalytic poison

• activators

• inhibitors

In ester hydrolysis, initally, the rate of the reaction is very slow. But after some time the rate increases because of presence of

• ester

• water

• acetic acid

• HCl