Effect of Catalyst on Rates of Reaction

Briefly explain the effect of adding catalyst on the rate of a reaction.

The rate of reaction increases in presence of catalyst. Explain the statement by plotting a curve between reaction coordinate and energy.

What is the effect of adding catalyst on the free energy change ($△\mathrm{G}$) of a reaction?

The factors which influence the rate of reaction are :

Concentration: Greater the concentrations of the reactants, faster is the rate of reaction.

Temperature: The rate of reaction increases with increase in temperature. For most of the reactions, the rate of reaction becomes almost double with 10o rise in temperature.

Presence of catalyst: A catalyst generally increases the speed of a reaction.

Answer the following question :

The role of a catalyst is to change _____.

Which of the following statements are not correct regarding rate of catalyst in a chemical reaction?
i. Changes the $\mathrm{\Delta H}$ of the reaction
ii. Decrease the activation energy for the forward and backward reaction equally
iii. Provides a new path of higher activation energy
iv. Increases the average kinetic energy of reacting molecules

Which of the following is NOT the function of catalyst?

The role of a catalyst is to change _____.

Consider the reaction

${\mathrm{Tl}}^{+}\left(\mathrm{aq}\right)+2{\mathrm{Ce}}^{4+}+\left(\mathrm{aq}\right)\to {\mathrm{Tl}}^{3+}+\left(\mathrm{aq}\right)+2{\mathrm{Ce}}^{3+}\left(\mathrm{aq}\right)$ The rate law for the reaction is rate =$\mathrm{k}$ $\left[{\mathrm{Ce}}^{4+}\right] \left[{\mathrm{Mn}}^{2+}\right].$ In the presence of ${\mathrm{Mn}}^{2+}$the reaction occurs in the following elementary steps:

${\mathrm{Ce}}^{4+ }\left(\mathrm{aq}\right)+{\mathrm{Mn}}^{2+}\left(\mathrm{aq}\right) \to {\mathrm{Ce}}^{3+}\left(\mathrm{aq}\right)+{\mathrm{Mn}}^{3+} \left(\mathrm{aq}\right)$

${\mathrm{Ce}}^{4+}\left(\mathrm{aq}\right)+{\mathrm{Mn}}^{3+}\left(\mathrm{aq}\right)\to {\mathrm{Ce}}^{3+}\left(\mathrm{aq}\right)+{\mathrm{Mn}}^{4+}\left(\mathrm{aq}\right)$

${\mathrm{Tl}}^{+}\left(\mathrm{aq}\right)+{\mathrm{Mn}}^{4+}\left(\mathrm{aq}\right)⟶{\mathrm{Tl}}^{3+}\left(\mathrm{aq}\right)+{\mathrm{Mn}}^{2+}\left(\mathrm{aq}\right)$

Identify (a) catalyst.

Comment on the effect of catalyst on rate of reverse reaction.

Comment on the effect of catalyst on rate of forward reaction.

The rate law for the reaction $2\mathrm{NO} \left(\mathrm{g}\right)+ {\mathrm{CI}}_2 \left(\mathrm{g}\right) \to 2\mathrm{NOCl} \left(\mathrm{g}\right)$ is given by rate $= \mathrm{k} \left[\mathrm{NO}\right] \left[{\mathrm{Cl}}_2\right]$ . The reaction occurs in the following steps:
(i) $\mathrm{NO} \left(\mathrm{g}\right)+{\mathrm{CI}}_2 \to {\mathrm{NOCI}}_2\left(\mathrm{g}\right)$

(ii) ${\mathrm{NOCI}}_2 \left(\mathrm{g}\right)+ \mathrm{NO} \left(\mathrm{g}\right) \to 2\mathrm{NOCl} \left(\mathrm{g}\right)$

Is ${\mathrm{NOCI}}_2$ a catalyst or reaction intermediate? Why?

A certain reaction occurs in the following steps:

(i) $\mathrm{Cl}\left(\mathrm{g}\right)+{\mathrm{O}}_3\left(\mathrm{g}\right)\to \mathrm{ClO}\left(\mathrm{g}\right)+{\mathrm{O}}_2\left(\mathrm{g}\right)$

(ii) $\mathrm{ClO} \left(\mathrm{g}\right)+ \mathrm{O} \left(\mathrm{g}\right)\to \mathrm{Cl}\left(\mathrm{g}\right)+ {\mathrm{O}}_2 \left(\mathrm{g}\right)$
Identify the catalyst.

Consider the reaction ${\mathrm{Tl}}^{+}\left(\mathrm{aq}\right)+2{\mathrm{Ce}}^{4+}+\left(\mathrm{aq}\right)\to {\mathrm{Tl}}^{3+}+\left(\mathrm{aq}\right)+2{\mathrm{Ce}}^{3+}\left(\mathrm{aq}\right)$ 

The rate law for the reaction is rate =$\mathrm{k}$ $\left[{\mathrm{Ce}}^{4+}\right] \left[{\mathrm{Mn}}^{2+}\right].$

In the presence of ${\mathrm{Mn}}^{2+}$the reaction occurs in the following elementary steps:

${\mathrm{Ce}}^{4+ }\left(\mathrm{aq}\right)+{\mathrm{Mn}}^{2+}\left(\mathrm{aq}\right) \to {\mathrm{Ce}}^{3+}\left(\mathrm{aq}\right)+{\mathrm{Mn}}^{3+} \left(\mathrm{aq}\right)$

${\mathrm{Ce}}^{4+}\left(\mathrm{aq}\right)+{\mathrm{Mn}}^{3+}\left(\mathrm{aq}\right)\to {\mathrm{Ce}}^{3+}\left(\mathrm{aq}\right)+{\mathrm{Mn}}^{4+}\left(\mathrm{aq}\right)$

${\mathrm{Tl}}^{+}\left(\mathrm{aq}\right)+{\mathrm{Mn}}^{4+}\left(\mathrm{aq}\right)⟶{\mathrm{Tl}}^{3+}\left(\mathrm{aq}\right)+{\mathrm{Mn}}^{2+}\left(\mathrm{aq}\right)$

Identify (b) intermediate.

Comment on the effect of catalyst on activation energy.

How does a catalyst differ from reaction intermediate?

What are the requirements for a bimolecular reaction to take place?

Explain, with the help of potential energy barrier, how does a catalyst increase the speed of a reaction.

What is the effect of catalyst on rate of reaction? Give graphical representation.

A catalyst is a substance which

Which of the following processes does not involve a catalyst?