Question 1

The graph between log  \dfrac { X }{ m }  v/s log P is straight-line inclined at an angle  45^o  with intercept 0.30. What will be the rate of adsorption at pressure of 0.4 atm?

Accepted Answer

Slope in equation is  \dfrac{1}{n}  = tan 45^o  =1
Intercept is logk = 0.30, that implies k=2
Hence by equation  \dfrac{x}{m} = kp^{1/n}  k=2, n=1 and p=0.4 	herefore  Rate of adsorption, x/m is 0.8.Option C is correct.

Question 2

Which one of the following is an example of homogeneous catalysis?

Accepted Answer

Hint: Homogenous catalysts are those in which the catalyst is in the same phase as the reactants and products.Explanation:A)  Haber's process: It combines nitrogen from the air with hydrogen derived mainly from natural gas (methane) into ammonia using Iron oxide catalyst at higher temperature and pressure. The reaction is shown as;  N_{2(g)} +3H_{2(g)} \xrightarrow{FeO_{(s)}} 2NH_{3(g)} Here, Catalyst is in Solid-phase while reactants are in gases phases. So, it is an example of heterogeneous catalysis.B) Contact process: It involves the following steps:1. makes sulfur dioxide by burning sulfur in excess of air/oxygen.2. converts the sulfur dioxide into sulfur trioxide in the presence of a catalyst vanadium pentoxide ( V_2O_5 V2O5)Reaction is shown as; SO_{2(g)} + 0.5O_{2(g)} \xrightarrow{V_2O_{5(s)}} SO_{3(g)} Here, Catalyst is in Solid-phase while reactants are in gases phases. So, it is an example of heterogeneous catalysis.C)  Catalytic hydrogenation is the addition of hydrogen to an unsaturated compound with a double or triple bond such as oil. The process of catalytic hydrogenation utilizes a metal catalyst such as nickel, palladium, or platinum. the reaction is shown as;  Unsaturated_{(l)} +H_{2(g)} \xrightarrow{Ni_{(s)}} Saturated_{(l)} Here, Catalyst is in Solid-phase while reactants are in gases phases. So, it is an example of heterogeneous catalysis.D)  Acid hydrolysis of methyl acetate is catalyzed by dilute acid, where it gets converted to methanol and acetic acid. The reaction is shown as; MeOCOCH_{3(aq.)} + H_2O_{(l)} \xrightarrow{H^+_{(aq)}} MeOH_{(aq.)} + AcOH_{(aq.)} Here catalyst and the reactants both are in the liquid (Aqueous) phase so it is an example of Homogenous catalysis.Final answer:  Correct Option is  D

Question 3

Which of the following statements regarding enzyme inhibition is correct ?

Accepted Answer

Competitive inhibition is seen when the substrate and the inhibitor compete for the active site on the enzyme because a competitive inhibitor has a similar structure as that of a substrate, so it blocks the active site of an enzyme thereby reducing the production formation.Hence, option C is correct.

Question 4

Which of the following is not correct for enzyme catalysis?

Accepted Answer

Enzymes are macromolecular biological catalysts. Enzymes accelerate chemical reactions. The molecules upon which enzymes may act are called substrates and the enzyme converts the substrates into different molecules known as products. Enzyme catalysis is unique in its efficiency and high degree of specificity.Enzymes are Highly specific nature.This says that enzyme is specific for a given reaction.Enzymes are highly active under optimum temperature.The optimum temperature range for enzymatic activity is 298-310K.Enzymes are highly active under optimum pH.Optimum pH level is between 5-7.The activity of enzymes gets increased in presence of activators and co-enzymes.

Question 5

In the presence of a catalyst, the heat evolved or absorbed during the reaction:

Accepted Answer

The enthalpy change value of the reaction will not be affected by a catalyst. A catalyst will only lower the required activation energy for the reactions. Since it will lower the activation energy for both the forward and reverse reactions to the same extent, the net change in enthalpy is zero.

Question 6

Which of the following statements about a catalyst is/are true?

Accepted Answer

Hint: A catalyst does not affect the thermodynamic parameters of a reaction such as enthalpy, entropy, Gibbs energy, and equilibrium constant. Explanation for Correct Answer:A catalyst increases the rate of the reaction by lowering the activation energy.The diagram suggests the activation energy with the catalyst and without the catalyst as below;As Catalyst increases the reaction rate by lowering the activation energy, So, Option A is correct.Catalyst does not take part actively in the reaction, it just is consumed in one step and regenerated in another step. and it requires in a very small quantity. So, Option B is also correct.Explanation for Incorrect Answer:A catalyst does not affect the thermodynamic parameters of a reaction. So, Option C is IncorrectA catalyst does not affect the equilibrium constant of a reaction. It just speeds up the rate of attainment of equilibrium. So, Option D is Incorrect.Final answer: Option  A  and  B .

Question 7

Select the correct statement from the following.

Accepted Answer

\bullet \quad  Addition of Catalyst has no effect on the value of
equilibrium constant.

\bullet \quad  Catalyst increases the rate of forward and backward reaction
in equal proprtional.

\bullet \quad  The ratio of mixture at equilibrium does not change by
catalyst.

\bullet \quad  Catalyst may be of solid, liquid or gaseous
state.

Question 8

What is a catalyst? give one example.

Accepted Answer

A catalyst is substance i.e a element or a compound that increases the rate of chemical reaction. Examples: 1) Nickel, Ni is used in hydrogenation of palm oil into margarine.2) Iron, Fe is used in Haber process. (Manufacturing of ammonia)

Question 9

Study of digestion of starch by salivary amylase and effect of  pH  and temperature on it.

Accepted Answer

A. Digestion of Starch by Salivary amylase:-1. 2 test tubes are taken with some water and is labeled. 2 tsp of boiled rice is added in one tube and 2 tsp of boiled rice that has been chewed for  2-3  minutes is added to another tube.2. A few drops of iodine is added to both the tubes.Results - The tube with the boiled rice turns blue due to the reaction of starch with iodine. The tube with the chewed rice does not change colour. This is because salivary amylase acts on the starch in the rice during chewing and breaks down the starch into smaller sugar units.B. Effect of pH:-1. Take 3 test tubes with 2 ml starch solution and label them. Add  1 ml  of saliva solution to each tube. Add  1 ml  each of water,  NaOH solution, and dil. HCl  solution to the respective tubes.2. After a few minutes, a few drops of iodine solution is added to each tube.Results - The activity of salivary amylase is the best at pH of  6 - 7  with the highest at a pH of  6.8 . So, it means that the activity of salivary amylase is good under acidic to neutral conditions. So, the blue colour will be more in the tube with the NaOH as there will be no activity of the salivary amylase on the starch solution. The blue colour will be light in the tube with water and a very little in the tube with dil.HCl. However, it will fade away soon and there will no colour. This is because the salivary amylase is active in acidic pH and so it will break down the starch to smaller glucose molecules.C. Effect of temperature.1. The test tubes are labeled and  2ml  of saliva solution and 4 ml of starch solution is taken in each tube.2. The test tubes are kept in water baths of  37°C, 50°C , and one in boiling water. After a few minutes, the test tubes are removed and a few drops of Iodine is added.Results - The activity of salivary amylase is maximum at a temperature of  32 - 37°C.  At high temperature, the enzyme gets denatured and at lower temperatures, the enzyme is not active, so the enzyme activity does not occur. So, the test tube at  37°C  turns blue first but eventually becomes colourless. The other test tubes have blue colored solutions.

Question 10

The catalyst used in making  H_2SO_4  in contact process is :

Accepted Answer

The contact process is the current method of producing sulfuric acid in the high concentrations needed for industrial processes. Platinum used to be the catalyst for this reaction. However, as it is susceptible to reacting with arsenic impurities in the sulfur feedstock, vanadium(V) oxide  (V_2O_5)  is now preferred.

Revise with Concepts

Catalyst

Catalysts in Industry

Adsorption Theory of Catalysis

Zeolite Catalysis

Enzyme Catalysis

Learn with Videos

Quick Summary With Stories

Introduction to Catalysis

Adsorption Theory of Heterogeneous Catalysis

Zeolite Catalysis

Introduction to Enzyme Catalysis

Important Questions

The graph between log $\frac{X}{m}$ v/s log P is straight-line inclined at an angle $4 5^{o}$ with intercept 0.30. What will be the rate of adsorption at pressure of 0.4 atm?

Which one of the following is an example of homogeneous catalysis?

Which of the following statements regarding enzyme inhibition is correct ?

Which of the following is not correct for enzyme catalysis?

In the presence of a catalyst, the heat evolved or absorbed during the reaction:

Which of the following statements about a catalyst is/are true?

Select the correct statement from the following.

What is a catalyst? give one example.

Study of digestion of starch by salivary amylase and effect of $p H$ and temperature on it.

The catalyst used in making $H_{2} S O_{4}$ in contact process is :

Revise with Concepts

Catalyst

Catalysts in Industry

Adsorption Theory of Catalysis

Zeolite Catalysis

Enzyme Catalysis

Learn with Videos

Quick Summary With Stories

Introduction to Catalysis

Adsorption Theory of Heterogeneous Catalysis

Zeolite Catalysis

Introduction to Enzyme Catalysis

Important Questions

The graph between log mX​ v/s log P is straight-line inclined at an angle 45o with intercept 0.30. What will be the rate of adsorption at pressure of 0.4 atm?

Which one of the following is an example of homogeneous catalysis?

Which of the following statements regarding enzyme inhibition is correct ?

Which of the following is not correct for enzyme catalysis?

In the presence of a catalyst, the heat evolved or absorbed during the reaction:

Which of the following statements about a catalyst is/are true?

Select the correct statement from the following.

What is a catalyst? give one example.

Study of digestion of starch by salivary amylase and effect of pH and temperature on it.

The catalyst used in making H2​SO4​ in contact process is :

The graph between log $\frac{X}{m}$ v/s log P is straight-line inclined at an angle $4 5^{o}$ with intercept 0.30. What will be the rate of adsorption at pressure of 0.4 atm?

Study of digestion of starch by salivary amylase and effect of $p H$ and temperature on it.

The catalyst used in making $H_{2} S O_{4}$ in contact process is :