Theories of Catalysis

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

1. adsorption lowers the activation energy of the reaction.
2. concentration of reactant molecules at the active centers of the catalyst becomes high due to adsorption.
3. adsorption increases the activation energy of the reaction.
4. None of the above

Q. $CO+H_2\to {300}^{\circ }C/300$ atm X(catalyst) $C{H}_{3}OH$
The catalyst X is

1. Fe
2. $\frac{C{r}_2{O}_3}{ZnO}$
3. $V_2{O}_5$
4. $A{l}_2{O}_3$

Q. $i\left)2H_2{O}_2\stackrel{}{\underset{\mathrm{Pt}}{\to }2H_{2}O+O_2}\mathrm{ii}\right)2H_2{O}_2\stackrel{}{\underset{\mathrm{Glycerol}}{\to }2H_2}O+O_2$
What is the role of $Pt$ and glycerol in the above reaction?

1. Both act as negative catalysts
2. Both act as positive catalysts
3. $Pt$ acts as a negative catalyst and glycerol acts as a positive catalyst
4. $Pt$ acts as a positive catalyst and glycerol acts as a negative catalyst

Q. The role of a catalyst in a reversible reaction is to

1. Increase the rate of forward reaction
2. Decrease the rate of backward reaction
3. Alter the equilibrium constant of the reaction
4. Allow the equilibrium to be achieved quickly

Q.

What is the role of a catalyst in a catalysed reaction

[MP PMT 1996; Pb. PMT 2000;UPSEAT 2001, 02]

1. Lowers the activation energy

2. Increases the activation energy

3. Affects the free energy change

4. Affects the enthalpy change