CHEMICAL KINETICS MCQs

CHEMICAL KINETICS

The rate at which a substance reacts depends on its

  1. Molecular mass
  2. Atomic mass unit
  3. Atomic mass
  4. Active mass

Active mass

The branch of chemistry which deals with the ate and mechanism of a reaction is called _____ .

  1. Chemical kinetics.
  2. Classical thermodynamics
  3. Wave mechanism
  4. Photochemistry

Chemical kinetics

The change in the concentration of the reactant or product per unit time is called

  1. Rate of reaction
  2. Molecularity of the reaction.
  3. Rate constant
  4. Order of the reaction

Rate of reaction

Usually the rate of the reaction is expressed as

  1. mol dm-3
  2. mol2 dm-2 s-1
  3. mol dm-2 s-1
  4. mol dm-3 s-1

mol dm-3 s-1

Chemical kinetics is helpful and used to study

  1. Mechanism of reaction
  2. Effect of temperature on reaction rate
  3. Rate of reaction
  4. All of A, B, and C

All of A, B, and C

The reaction in which the rate independent of concentration is called ____ .

  1. Zero order
  2. First order
  3. Second order
  4. Third order

Zero order

The Arrhenius equation accounts for the rate of chemical reaction in terms of?

  1. Activation energy
  2. Molecularity of reaction
  3. Order of reaction
  4. Physical state

Activation energy

The dimension for first order rate constant is

  1. s
  2. s mol-1
  3. mol-1 S-1
  4. s-1

s-1

The rate constant of a reaction depends on

  1. Concentration of reactants
  2. Concentration of products
  3. Temperature
  4. Pressure

Temperature

The rate constant of a reaction has same units as the rate of the reaction. The reaction is of

  1. Zero order
  2. First order
  3. Second order
  4. Third order

Zero order

The rate constant for 3rd order reaction has the dimension of which of the following?

  1. mol-2 s-1
  2. I-1 mol-1 s-1
  3. mol I-1 s-1
  4. I2 mol-2 s-1

I2 mol-2 s-1

Which factors affect the rate of the reaction?

  1. Concentration
  2. Pressure
  3. Temperature
  4. All of A, B, and C

All of A, B, and C

For a reaction of the type A+B → Products, It is observed that doubling the concentration of A causes the reaction rate to be four times as great, but doubling the amount of B there is no apparent effect on the rate. The rate equation is

  1. Rate = k | A |2
  2. Rate = k | AI | B |
  3. Rate = k | A |2 | B |
  4. Rate = k | A |2 | B |2

Rate = k | A |2

Suppose we have a reaction 2A + B → C+D. The rate of the reaction increase eight times when the concentrations of both A and B are doubled. The rate of the reaction increase four times when the initial concentration of only B is doubled. What is the rate expression for the reaction?

  1. r = k | A |2 | B |
  2. r = k | A |2 | B |2
  3. r = k | A | | B |
  4. r = k | A | | B |2

r = k | A | | B |2

For an elementary reaction 2A + B → C + D The molecularity of the reaction is

  1. 4
  2. 3
  3. 2
  4. 1

3

A second order rate constant has the dimension of  which of the following?

  1. dm-6 mol2 s-1
  2. dm³ mol-1 s-1
  3. dm I-2 s-1
  4. dm3 mol s-1

dm³ mol-1 s-1

Which is an acceptable value of the molecularity?

  1. 2.5
  2. 0
  3. 2
  4. 8

2

Which statement about molecularity is not true?

  1. It cannot be more than 3
  2. It can be obtained from balanced equation
  3. It may be or may not be equal to the order of the reaction
  4. It cannot be fraction

It cannot be more than 3

law is forever is different from the expression of law of mass action

From an elementary reaction of the type A+ 2B → C + D, What is the order of the reaction?

  1. 2
  2. 3
  3. Cannot be determined
  4. Zero

Cannot be determined

The following mechanism has been proposed for a reaction 2A+B → D+E, A+B→C+D (slow), A+C →E (fast). What is the rate expression for the reaction?

  1. r = k | A | | B |
  2. r = k | A |2 | B |
  3. r = k | A |2
  4. r = k | A | | C |

r = k | A | | B |

For a chemical reaction A → products, the rat of the reaction doubles when the concentration of A is increased by 4 times. What is the order of the reaction?

  1. 0.5
  2. 0
  3. 2
  4. 1

0.5

The minimum amount of energy that the ting molecules must possess at the time of collisions in order to produce effective collisions is called________ .

  1. Free energy
  2. External energy
  3. Internal energy
  4. Activation energy

Activation energy

What is the order of reaction of radioactive decay?

  1. Zero
  2. 2
  3. 1
  4. 3

Zero

Point out the false statement.

  1. Rate law is an experimental fact whereas law of mass action is a theoretical in nature
  2. Order of the reaction is equal to the sum of the exponents of concentration terms in the rate law
  3. Rate law is more informative than law of mass action
  4. law is forever is different from the expression of law of mass action

For a hypothetical reaction A+B Products, the rate law is r = k| B || A |2. What is the order of the reaction?

  1. 2
  2. 3
  3. 0
  4. 1

2

The hydrolysis of methyl acetate reaction of

  1. Zero order
  2. Second order
  3. Third order
  4. First order

First order

Suppose, CA is the concentration of A at any time and C0A is its concentration at t = 0, then, for a zero-order reaction of the type A→ Products,  the rate equation can be written as ______ .

  1. CA – C0A =0
  2. CA = C0A – kt
  3. CA/C0A = k
  4. CA =C0A – k

CA =C0A – k

In multistep reaction, Which is the slowest step?

  1. Mechanism step
  2. Enthalpy determining step
  3. Rate determining step
  4. None of A, B, and C

Rate determining step

The half-life period of any first order reaction

  1. Is independent of the initial concentration
  2. Is half the specific rate constant
  3. Is forever the same whatever the reaction
  4. Is directly proportional to the initial concentration of the reactant

Is independent of the initial concentration

Which methods are/is helpful and used to determine the rate of the reaction?

  1. Polarimetry
  2. Conductometry
  3. Spectroscopy
  4. All of A, B, and C

Spectroscopy

Which technique is helpful and used to measure absorption of radiation?

  1. Conductometry
  2. Polarimetry
  3. Dilatometry
  4. Spectrophotometry

Spectrophotometry

For the first-order reaction with rate constant k, the half-life period (initial concentration = a) is equal to

  1. 1/ka1/2
  2. 1/ka
  3. 0.693/ka
  4. ln2/k

ln2/k

Why catalyst increases the rate of a reaction?

  1. It provides the necessary energy to the colliding molecules to cross energy barrier
  2. It provides a different path of lower activation energy
  3. It decreases the order of the reaction
  4. It decreases the heat of the reaction

It provides a different path of lower activation energy

Chemical reactions of the type A-ki→B-k2→C are called

  1. Pseudo chemical reactions
  2. Consecutive reactions
  3. Parallel reactions
  4. Fast reactions

Consecutive reactions

In dilatometric method, the rate of reaction is measured by change in

  1. Pressure
  2. Conductance
  3. Concentration
  4. Volume

Volume

The rate of reaction between two specific time intervals is called

  1. Rate constant
  2. Instantaneous rate
  3. Average rate
  4. Rate of reaction

Average rate

The equation for the rate constant is given by k= p Ze-Ea/RT. A chemical reaction will proceed more rapidly if there is a decrease in

  1. E
  2. Z
  3. T
  4. P

E

The large increase in the rate of a reaction on rise in temperature is due to

  1. The increase in the number of molecules having more than the threshold energy
  2. The decrease in mean free path
  3. The increase in collision frequency
  4. The lowering of activation energy

The increase in the number of molecules having more than the threshold energy

In the kinetic study of a reaction A → Products A straight line was observed when a graph between time and 1/C2 was plotted, the reaction is

  1. Second order
  2. First order
  3. Zero order
  4. Third order

Third order

Which is not a true, characteristic of a catalytic reaction?

  1. The amount and chemical composition of the catalyst remains unchanged after the reaction
  2. The catalyst shifts the equilibrium position of a reaction in a helpable direction
  3. The reaction in which products also act as catalysis are called auto-catalysed reactions
  4. The catalyst does not initiate a chemical reaction

The catalyst shifts the equilibrium position of a reaction in a helpable direction

Which statement is not related to collision theory?

  1. Molecules must collide with each other to do a chemical reaction
  2. Collision theory is applicable to liquids only
  3. Molecules must have proper orientation
  4. Molecules must possess a minimum amount of energy

Collision theory is applicable to liquids only

The experimental relationship between rate of the reaction and concentration of the reactants is called

  1. Rate constant
  2. Law of mass action
  3. Le-Chatelier’s principle graph
  4. Rate law

Rate law

A substance which itself is not a catalyst but increases the activity of a catalyst is called

  1. Inhibitor
  2. Poison
  3. Enzyme
  4. Promoter

Promoter

Which expressions represent the Arrhenius equation?

  1. k = e-Ea/K
  2. k = Ae–Ea/RT
  3. k = Ae–Ea/T
  4. k = Ae-Ea/R

k = Ae–Ea/RT

Which is true for Enzymes?

  1. Proteins
  2. Inorganic compounds
  3. Moulds
  4. Microorganisms

Proteins

The maximum value of order of a reaction helpful and used to may be

  1. 2
  2. 1
  3. 4
  4. 3

4

Which property of the liquid is measured by polarimetry?

  1. Optical activity
  2. Transmittance
  3. Absorbance
  4. Conductance

Optical activity

The rate constant of first order reaction depends on

  1. Temperature
  2. Time
  3. Catalyst
  4. Concentration

Temperature

What is the half-life period for zero order reaction?

  1. Is independent of initial concentration
  2. Is proportional to initial concentration
  3. Is inversely proportional to initial concentration
  4. Is proportional to square of concentration

Is proportional to initial concentration

What is the temperature coefficient of a reaction?

  1. The specific rate constant at 25°C.
  2. The rate of a reaction at 25°C
  3. The ratio of rate constant at two different temperatures differing by 1°C
  4. The ratio of rate constant at 35 °C and 65. T 25°C

The ratio of rate constant at 35 °C and 65. T 25°C

The half-life period for a zero order reaction.

  1. t1/2 = k/2a2
  2. t1/2 = 2k/a
  3. t1/2 = a2/2k
  4. t1/2 = a/2k

t1/2 = a/2k

Which metals are usually helpful and used as catalyst?

  1. Transition metals
  2. Coinage metals
  3. Alkaline earth metals
  4. Alkali metals

Transition metals

The rate constant for the zero order reaction is given by

  1. k = (C0 – C1)/t
  2. k = C0/2t
  3. k = C0/C1
  4. k= ln [(C0-C₁)/2t]

k = (C0 – C1)/t

When the initial concentration of the reaction is increased 3 times, the half-life period also increases 3 fold. The order of the reaction is

  1. Two
  2. Three
  3. Zero
  4. One

Zero

The order of reaction of saponification of ethyl acetate is

  1. One
  2. Zero
  3. Two
  4. Three

Zero

For the first order reaction, the slope of the plot of log[A], verses tis

  1. -k/2.303
  2. k

C.–k

  1. k/2.303

–k

What is the order of  reaction, 2H2O2 2H2O+ O2?

  1. Zero order
  2. Third order
  3. Second order
  4. First order

Second order

For the second order reaction, the slope of the plot of 1/[A]t verses t is

  1. -k/2.303
  2. k
  3. –k
  4. k/2.303

k

The plot of logk verses 1/T is a linear with a slope

  1. -Ea/2.303R
  2. Ea/R
  3. –Ea/R
  4. Ea/2.403R

-Ea/2.303R

A plot of log k versus 1/T of a reaction gives a straight line with

  1. a non-zero intercept and positive slope
  2. a non-zero intercept and negative slope
  3. a zero intercept and negative slope
  4. a zero intercept and positive slope

a non-zero intercept and negative slope

For a first order reaction a plot of log [A] versus time gives a straight line with:

  1. a zero intercept and positive slope
  2. a non-zero intercept and negative slope
  3. a zero intercept and negative slope
  4. a non-zero intercept and positive slope

a non-zero intercept and negative slope

More Physical Chemistry MCQs

  1. PHYSICAL CHEMISTRY MCQs
  2. CHEMICAL AND IONIC EQUILIBRIA MCQs
  3. NUCLEAR CHEMISTRY MCQs
  4. CHEMICAL THERMODYNAMICS MCQs
  5. NANOCHEMISTRY MCQs
  6. CHEMICAL KINETICS MCQs
  7. SURFACE CHEMISTRY MCQs
  8. COLLOIDAL STATE MCQs
  9. ELECTROCHEMISTRY MCQs
  10. SPECTROSCOPY MCQs
  11. SOLUTION CHEMISTRY AND PHASE EQUILIBRIA MCQs
  12. PHOTOCHEMISTRY AND MOLECULAR SYMMETRY MCQs
  13. CHEMISTRY MCQs From all subjects of  Chemistry

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