Question Bank Directory

$^{235}_{92}U$ nucleus absorbs a neutron and disintegrates into $^{139}_{54}Xe$, $^{94}_{38}Sr$ and $x$. The product $x$ is:

If at a given instant, for the reaction $2N_2O_5 \rightarrow 4NO_2 + O_2$ rate and rate constant are $1.02 \times 10^{-4}$ and $3.4 \times 10^{-5} \text{ sec}^{-1}$ respectively, then the concentration of $N_2O_5$ at that time will be:

The reaction A $\rightarrow$ B follows first-order kinetics. The time taken for $0.8 \text{ mol}$ of A to produce $0.6 \text{ mol}$ of B is $1 \text{ hour}$. The time taken for the conversion of $0.9 \text{ mol}$ of A to produce $0.675 \text{ mol}$ of B will be:

The radioisotope, tritium ($^3_1H$) has a half-life of 12.3 years. If the initial amount of tritium is 32 mg, how many milligrams of it would remain after 49.2 years:

The activation energy of a reaction can be determined from the slope of the graph between:

The rate of a first-order reaction is $0.04 \text{ mol L}^{-1} \text{ s}^{-1}$ at $10 \text{ sec}$ and $0.03 \text{ mol L}^{-1} \text{ s}^{-1}$ at $20 \text{ sec}$ after initiation of the reaction. The half-life period of the reaction is

In a first order reaction $A \rightarrow B$, if $k$ is rate constant and initial concentration of the reactant A is $0.5 \text{ M}$ then the half-life is:

For an endothermic reaction, energy of activation is $E_a$ and enthalpy of reaction is $\Delta H$ (both of these in kJ/mol). Minimum value of $E_a$ will be:

In the reaction, $\text{BrO}_3^-(aq) + 5\text{Br}^-(aq) + 6\text{H}^+(aq) \rightarrow 3\text{Br}_2(l) + 2\text{H}_2\text{O}(l)$ The rate of appearance of bromine ($\text{Br}_2$) is related to rate of disappearance of bromide ions as following:

For a reaction $A \rightarrow B$, enthalpy of reaction is $-4.2 \text{ kJ mol}^{-1}$ and enthalpy of activation is $9.6 \text{ kJ mol}^{-1}$. The correct potential energy profile for the reaction is:

The slope of Arrhenius Plot ($\ln k$ v/s $1/T$) of the first-order reaction is $-5 imes 10^3 \text{ K}$. The value of $E_a$ of the reaction is: [Given $R = 8.314 \text{ J K}^{–1} \text{ mol}^{–1}$]

For the reaction, $2A \rightarrow B$, $\text{rate} = k[A]^2$. If the concentration of reactant is doubled, then the: (a) rate of reaction will be doubled. (b) rate constant will remain unchanged, however rate of reaction is directly proportional to the rate constant. (c) rate constant will change since the rate of reaction and rate constant are directly proportional to each other. (d) rate of reaction will increase by four times. Identify the set of correct statements and choose the correct answer from the options given below:

The plot of $\ln k$ vs $1/T$ for the following reaction, $2N_2O_5(g) \rightarrow 4NO_2(g) + O_2(g)$ gives a straight line with the slope of the line equal to $-1.0 \times 10^4 \text{ K}$. What is the activation energy for the reaction in $\text{J mol}^{–1}$? (Given: $R = 8.3 \text{ J K}^{–1} \text{ mol}^{–1}$)

The correct option for the rate law that corresponds to an overall first-order reaction is:

For a chemical reaction, $4A + 3B \rightarrow 6C + 9D$ rate of formation of C is $6 \times 10^{–2} \text{ mol L}^{–1} \text{ s}^{–1}$ and rate of disappearance of A is $4 \times 10^{–2} \text{ mol L}^{–1} \text{ s}^{–1}$. The rate of reaction and amount of B consumed in interval of 10 seconds, respectively will be:

The rate of a reaction quadruples when temperature changes from $27^{\circ}\text{C}$ to $57^{\circ}\text{C}$. Calculate the energy of activation. Given $R = 8.314 \text{ J K}^{–1} \text{ mol}^{–1}$, $\log 4 = 0.6021$

The half-life for a zero-order reaction having 0.02 M initial concentration of reactant is 100 s. The rate constant (in mol L⁻¹ s⁻¹) for the reaction is:

What does $Z_{AB}$ represent in the collision theory of chemical reactions?

The 2-chlorobutane obtained by chlorination of n-butane will be:

Anisole on cleavage with HI gives