Chemical Kineti...

Assertion: For each ten degree rise of temperature, the specific constant rate is nearly doubled.
Reason: Energy-wise distribution of molecules in a gas is an exponential function of temperature.

Assertion: The rate of reaction is accelerated by the presence of catalyst.
Reason: The presence of catalyst makes the value of ∆G˚ more negative.

Assertion: The reaction 2NO + O₂ → 2NO₂ and CO₂ + O₂ → 2CO₂ proceed at the same rate because they are similar.
Reason: Both the reactions have the same activation energy.

Assertion: In rate laws, unlike the expression for equilibrium constants, the exponents for concentrations do not necessarily match the stoichiometric coefficients.
Reason: It is the mechanism and not the balance chemical equation for the overall change that governs the reaction rate.

Assertion: The molecularity of reaction: H₂ + Br₂ → HBr is 2.

Reason: The order of this reaction is 3/2.

Assertion: The addition of catalyst lowers the activation barrier, yet there is no change in the enthalpy.
Reason: Enthalpy image is equal to the difference in the activation energies for the forward and the backward reactions.

Assertion: A photochemical reaction that can take place in presence of red light can also take place in presence of violet light but the reverse is not true.
Reason: Red light has lower wave length than violet light.

Assertion: The photochemical reactions H₂ + Cl₂ → 2HCl and H₂ + Br₂ → 2HBr have equal quantum efficiencies.
Reason: Both the reactions proceed by similar mechanism.

Which of the following statements is/are wrong?

A. The rate of a reaction remains constant throughout the reaction.
B. The higher the activation energy of a reaction, the slower is the rate of the reaction.
C. For the reaction N₂ + 3H₂ → 2NH₃, the rate of reaction is same when expressed in terms of N₂, H₂ and NH₃.

Select the correct statement(s).

A. The order of reaction is never negative with respect to any reactant or product.
B. Rate of reaction and rate constant of a second order reaction have the same unit.
C. Order of a reaction can be fractional but molecularity is never fractional.

Choose the false statement(s)

A. The free energy change of a photochemical reaction is always negative for the reaction to be spontaneous.
B. For 10˚ rise the temperature, the rate of reaction is almost doubled because the number of collisions is almost double.
C. Order of the reaction is independent of the change in conditions such as temperature, pressure etc.

Which of the following statements is/are correct for reactions of first order?

A. Rate law is more informative than law of mass action for the development of mechanism.
B. For the reaction 2O₃ → 3O₂ order with respect to O₂ is negative.
C. The presence of catalyst lowers the activation energy barrier.

Which of the following statements is/are incorrect?

A. Rate law expression cannot be written from the stoichiometric equation.
B. Law of mass action expression can be written from the balance equation.
C. Rate of reaction and rate of constant have same units.

If the reaction rate at a given temperature becomes slow, then which of the following is/are true?

A. The free energy of activation is higher.
B. The free energy of activation is lower.
C. The initial concentration of the reactants remains the constant.

Consider the following statements:
The rate law for the acid catalysed hydrolysis of an ester being given as:
Rate = k[H⁺][ester] = k'[ester]
If the acid concentration is doubled at constant ester concentration,
A. the second order rate constant, k is doubled
B. the pseudo first order rate constant, k is doubled
C. the rate of the reaction is doubled

Which of the above statements are correct?