Chemical Kinetics — JEE Advanced PYQs

For a reversible reaction $\mathbf{R}\rightleftharpoons \mathbf{P}$, at constant temperature, both the forward and the backward reactions are first order elementary reactions with rate constant $k_f$ and $k_b$, respectively. At time zero, the concentration of …

For a first-order reaction $\mathbf{R}\to \mathbf{P}$ at a given temperature, $k$ is the rate constant. For this reaction, at the given temperature, the concentrations of $\mathbf{R}$ and $\mathbf{P}$ at a time $t$ are $[\mathbf{R}]$ and $[\mathbf{P}]$, respectively. The …

Consider a reaction $A+R\to$ Product. The rate of this reaction is measured to be $k[A][R]$. At the start of the reaction, the concentration of $R,[R{]}_0$, is 10-times the concentration of $A,[A{]}_0$. The reaction can be considered to be a pseudo first order reaction w …

Consider the following reaction,

which follows the mechanism given below: …

A sample initially contains only U-238 isotope of uranium. With time, some of the U-238 radioactively decays into Pb-206 while the rest of it remains undisintegrated.
When the age of the sample is $\mathbf{P}\times 10^8$ years, the ratio of mass of $\mathrm{Pb}-206$ to tha …

The plot of $\log {\mathrm{k}}_{\mathrm{f}}$ versus $\frac{1}{\mathrm{T}}$ for a reversible reaction $\mathrm{A}(\mathrm{g})\rightleftharpoons \mathrm{P}(\mathrm{g})$ is shown.

(see plot)

Pre-exponential factors for the forward and backward reactions are …

Match the rate expressions in LIST-I for the decomposition of X with the corresponding profiles provided in LIST-II. ${\mathrm{X}}_{\mathrm{s}}$ and k constants having appropriate units.

List-I
(I) rate $=\frac{\mathrm{k}[\mathrm{X}]}{{\mathrm{X}}_{\mathrm{s}}+[\mathrm{X}]}$ und …

For the following reaction

the rate of reaction is $\frac{\mathrm{d}[\mathbf{P}]}{\mathrm{dt}}=k[\mathbf{X}]$. Two moles of $\mathbf{X}$ are mixed with one mole of $\mathbf{Y}$ to make 1.0 L of solution. At 50 s, 0.5 …

Which of the following plots is(are) correct for the given reaction?
( $[\mathrm{P}{]}_0$ is the initial concentration of $\mathbf{P}$ )

${}_{92}^{238}\mathrm{U}$ is known to undergo radioactive decay to form ${}_{82}^{206}\mathrm{Pb}$ by emitting alpha and beta particles. A rock initially contained $68\times 10^{-6}\mathrm{g}$ of ${}_{92}^{238}\mathrm{U}$. If the number of alpha particles that it would emi …

In the decay sequence :
…

Consider the kinetic data given in the following table for the reaction $\mathrm{A}+\mathrm{B}+\mathrm{C}\to$ Product.

| Experiment No. | [A] $\left(\mathrm{mol}{\mathrm{dm}}^{-3}\right)$ | [B] $\left(\mathrm{mol}{\mathrm{dm}}^{-3}\right)$ | [C] …

The decomposition reaction $2{\mathrm{N}}_2{\mathrm{O}}_5(\mathrm{g})\stackrel{\Delta }{\to }2{\mathrm{N}}_2{\mathrm{O}}_4(\mathrm{g})+{\mathrm{O}}_2(\mathrm{g})$ is started in a closed cylinder under isothermal isochoric condition at an initial pressure of 1 atm. After …

For a first order reaction $\mathrm{A}(\mathrm{g})\to 2\mathrm{B}(\mathrm{g})+\mathrm{C}(\mathrm{g})$ at constant volume and 300 K, the total pressure at the beginning $(t=0)$ and at time $t$ are $P_0$ and $P_t$, respectively. Initially, only A is present with conc …

In a bimolecular reaction, the steric factor P was experimentally determined to be 4.5. The correct option(s) among the following is(are)

According to the Arrhenius equation,

A plot of the number of neutrons $(N)$ against the number of protons $(P)$ of stable nuclei exhibits upward deviation from linearity for atomic number, $Z>20$. For an unstable nucleus having $N/P$ ratio less than 1, the possible mode(s) of decay is(are)

A closed vessel with rigid walls contains 1 mol of ²³⁸₉₂U and 1 mol of air at 298 K. Considering complete decay of ²³⁸₉₂U to ²⁰⁶₈₂Pb, the ratio of the final pressure to the initial pressure of the system at 298 K is

For the elementary reaction $\mathbf{M}\to \mathbf{N}$, the rate of disappearance of $\mathbf{M}$ increases by a factor of 8 upon doubling the concentration of $\mathbf{M}$. The order of the reaction with respect to M is

In the reaction,

the time taken for 75% reaction of $P$ is twice the time taken for 50% reaction of $P$. The concentration of $Q$ varies with reaction time as shown in the figure. The overall order of the reaction is

In the nuclear transmutation

(X, Y) is(are)

The periodic table consists of 18 groups. An isotope of copper, on bombardment with protons, undergoes a nuclear reaction yielding element $\mathbf{X}$ as shown below. To which group, element X belongs in the periodic table ? …

An organic compound undergoes first-order decomposition. The time taken for its decomposition to 1/8 and 1/10 of its initial concentration are ${\mathrm{t}}_{1/8}$ and ${\mathrm{t}}_{1/10}$ respectively. What is the value of …

For the first order reaction

(A) the concentration of the reactant decreases exponentially with time.
(B) the half-life of the reaction decreases with increasin …

Bombardment of aluminum by $\alpha$-particle leads to its artificial disintegration in two ways, (i) and (ii) as shown. Products X, Y and Z respectively are,

Plots showing the variation of the rate constant (k) with temperature (T) are given below. The plot that follows Arrhenius equation is

The concentration of $R$ in the reaction $R\to P$ was measured as a function of time and the following data is obtained:

The order of the reaction is

For a first order reaction $\mathrm{A}\to \mathrm{P}$, the temperature ( T ) dependent rate constant ( $k$ ) was found to follow the equation $\log k=-(2000)\frac{1}{\mathrm{T}}+6.0$. The pre-exponential factor A and the activation energy …

The total number of $\alpha$ and $\beta$ particles emitted in the nuclear reaction ${}_{92}^{238}\mathrm{U}\to {}_{82}^{214}\mathrm{Pb}$ is

Under the same reaction conditions, initial concentration of $1.386\mathrm{mol}{\mathrm{dm}}^{-3}$ of a substance becomes half in 40 seconds and 20 seconds through first order and zero order kinetics, respectively. Ratio $\left(\frac{k_1}{k_0}\right)$ of the rate constants f …

STATEMENT-1 : The plot of atomic number ( $y$-axis) versus number of neutrons ( $x$-axis) for stable nuclei shows a curvature towards $x$-axis from the line of $45^{\circ }$ slope as the atomic number is increased.
and
STATEMENT-2 : Proton-proton electrostatic repulsions begin to …

A positron is emitted from ${}_{11}^{23}\mathrm{Na}$. The ratio of the atomic mass and atomic number of the resulting nuclide is

Consider a reaction $\mathrm{aG}+\mathrm{bH}\to$ Products. When concentration of both the reactants G and H is doubled, the rate increases by eight times. However, when concentration of G is doubled keeping the concentration of H fixed, the rate is doubled. The overall o …