Theories of Catalysis

Q. 15.why Fe[(NH3)6] +2 does not have d 2sp 3 hybridization and have sp 3d 2 hybridization

Q. what is the hybridization of [Co(NH3)6]2+ & [Co(NH3)6]3+ & [Cu(NH3)4]+ ?

Q. In Freundlich Adsorption isotherm, the value of $\frac{1}{n}$ is :

1. 1 in case of physical adsorption
2. 1 in case of chemisorption
3. between 0 and 1 in all cases
4. between 2 and 4 in all cases

Q.

Why is isopropanol used in DNA extraction?

Q. The variation of $\left(\frac{x}{m}\right)$ vs $P$ is plotted for a gas at different temperatures as shown above.
The correct order of temperature is :


Here,
$\left(\frac{x}{m}\right)$ denotes the Amount of gas adsorbed per unit mass of adsorbent
$P$ is the pressure of the gas.

1. $T_1>T_2>T_3$
2. $T_3>T_2>T_1$
3. $T_2>T_1>T_3$
4. $T_2>T_3>T_1$

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

1. Adsorption lowers the activation energy of the reaction.
2. Adsorption produces heat which increases the speed of the reaction.
3. In the process of adsorption, the activation energy of the molecules becomes large.
4. The concentration of the reactant molecules at the active centres of the catalyst becomes high due to adsorption.

Q. why transition metals form interstitial compunds?

Q.

What are the most common Transition Metals?

Q. Potential energy difference between the reactant and activated complex is called. The minimum amount of energy needed for the particles to react is

1. threshold energy
2. activation energy
3. kinetic energy
4. potential energy

Q.

Which catalyst is used in Haber-Bosch process.

Q. The activation energy of a reaction at a given temperature is found to be 2.303 RT J/mol . The ratio of rate constant to the Arrhenius factor is

Q.

The decomposition of hydrogen peroxide can be slowed by the addition of a small amount of acetamide. The latter acts as a

1. Inhibitor

2. Promoter

3. Detainer

4. Stopper

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. In the Freundlich adsorption isotherm, log $\left(\frac{x}{m}\right)=logk+\frac{1}{n}logp,$ the value of n is

1. any value from 0 to 1
2. a positive integer
3. a negative integer
4. a positive or a negative fractional number

Q. A particular adsorption process has the following characteristics: (i) It arises due to van der Waals force and (ii) it is reversible.
Identify the correct statement that describes the above adsorption process.

1. Adsorption is monolayer
2. Energy of activation is low
3. Adsorption increases with increases in temperature
4. Enthalpy of adsorption is greater than $100{\text{kJ mol}}^{-1}$

Q. Adsorption of gas on a surface follows Freundlich adsorption isotherm. Plot of $\log x/m$ versus $\log P$ gives a straight line with slope equal to $0.5$, then:
($x/m$ is the mass of the gas adsorbed per gram of adsorbent)

1. Adsorption is proportional to the square of pressure
2. Adsorption is independent to pressure
3. Adsorption is proportional to the pressure
4. Adsorption is proportional to the square root of pressure

Q. Which of the following statement(s) is/are true regarding Freundlich adsorption isotherm?

1. It holds good for a limited range of pressure of the gas, but generally, fails at high pressure.
2. At low pressure, the extent of adsorption linearly dependent
   on pressure.
3. The extent of adsorption will attain a saturation point at high pressure.
4. All of the above.

Q. For the plot of $\left(\frac{m}{x}\right)vs\frac{1}{P}$ of the Langmuir adsorption isotherm, the slope and y-intercept are respectively:
where,
$\frac{x}{m}$ is extent of adsorption
$P$ is temperature
$a$ and $b$ are Langmuir parameters

1. $a$ and $b$
2. $\frac{1}{a}$ and $\frac{b}{a}$
3. $\frac{1}{a}$ and $\frac{1}{b}$
4. $\frac{1}{a}$ and $b$

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

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

Q.

Dihydrogen gas is obtained from natural gas by partial oxidation with steam as per following endothermic reaction:

(a) Write as expression for Kp for the above reaction.

(b) How will the values of Kp and composition of equilibrium mixture be affected by

(i) Increasing the pressure

(ii) Increasing the temperature

(iii) Using a catalyst?

Q. Adsorption of a gas follows Freundlich adsorption isotherm
$x$ is the mass of the gas adsorbed on mass $m$ of the adsorbent. $P$ is the pressure of the gas

In the plot of ${\log }_e\left(\frac{x}{m}\right)$ vs ${\log }_{e}P$:
Here
$m=\text{slope}c=\text{Intercept}$

1. $m=\frac{1}{k}c={\log }_e\left(n\right)$
2. $m=\frac{1}{n}c={\log }_e\left(k\right)$
3. $m={\log }_e\left(k\right)c=\frac{1}{n}$
4. $m={\log }_e\left(n\right)c=\frac{1}{k}$

Q. Consider the following energy profile

Which of the following reactant is most suited for the above energy profile ?

1. 
2. 
3. 
4. 

Q. Adsorption of a gas follows Freundlich adsorption isotherm
$x$ is the mass of the gas adsorbed on mass $m$ of the adsorbent

The plot of $\log \left(\frac{x}{m}\right)$ vs $\log P$ is shown,

From the graph above, $\left(\frac{x}{m}\right)$ is proportional to:

1. $P^{3/2}$
2. $P^3$
3. $P^{2/3}$
4. $P^2$

Q. The slope of the straight line graph between log x/m and log P for the adsorption of a gas on solid at constant temperature is:
(Where, x = mass of the gas adsorbed, m = mass of adsorbent, P = pressure)

1. $1/n$
2. $n$
3. $\log k$
4. $k$

Q.

Which description best describes how a catalyst works?

Q. On Freundlich adsorption isotherm $x$ is the mass of the gas adsorbed on mass $m$ of the adsorbent. The plot of $\log \left(\frac{x}{m}\right)$ vs $\log P$ is shown,

From the graph above, $\left(\frac{x}{m}\right)$ is proportional to:

1. $P^{3/2}$
2. $P^4$
3. $P^{2/3}$
4. $P^3$

Q.

A catalyst either___________ or ____________ the rate of chemical change but itself remains_____________at the end of the reaction.

Q. Which of the following is/are correct about Freundlich's adsorption isotherm for gases and solutions?

1. $\frac{x}{m}=K{P}^{1/n}$
2. $\frac{x}{m}=\frac{1+bP}{a}$
3. $log\frac{x}{m}=logK+nlogP$
4. $log\frac{x}{m}=logK+\frac{1}{n}logP$

Q.

According to VBT, the shape of [NiCl₄]^-2 is tetrahedral and the hybridization state of Ni is:

1. d²sp³

2. sp³d²

3. sp³

4. dsp²

Q.

During the hydrogenation of oils, the substance which is commonly used as a catalyst

1. Finely divided Nickle
2. Pt
3. Pd or Cu
4. V₂O₅