Chemical Kinetics PYQs Set 10 (PDF)

Set 10 of 11 · Questions 271-300 of 311

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JEE Main Chemistry · Chemical Kinetics · Set 10 (Q271-300)

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271.
A person's wound was exposed to some bacteria and then bacterial growth started to happen at the same place. The wound was later treated with some antibacterial medicine and the rate of bacterial decay(r) was found to be proportional with the square of the existing number of bacteria at any instance. Which of the following set of graphs correctly represents the 'before' and 'after' situation of the application of the medicine?
[Given: $N =$ No. of bacteria, $t =$ time, bacterial growth follows $1^{st}$ order kinetics.]
1. (1)
2. (2)
3. (3)
4. (4)
272.
The results given in the below table were obtained during kinetic studies of the following reaction $2 A + B \to C + D 2 A + B \to C + D x$ and $Y$ in the given table are respectively
Experiment
$[A] / molL^{- 1}$
$[B] / molL^{- 1}$
Initial rate $molL^{- 1} min^{- 1}$
$I$
$0.1$
$0.1$
$6.00 \times 10^{- 3}$
$II$
$0.1$
$0.2$
$2.40 \times 10^{- 2}$
$III$
$0.2$
$0.1$
$1.20 \times 10^{- 2}$
$IV$
$X$
$0.2$
$7.20 \times 10^{- 2}$
$V$
$0.3$
$Y$
$2.88 \times 10^{- 1}$
1. (1) $0.4, 0.3$
2. (2) $0.3, 0.4$
3. (3) $0.4, 0.4$
4. (4) $0.3, 0.3$
273.
Correct statements regarding Arrhenius equation among the following are :(A) Factor $e^{- Ea / RT}$ corresponds to fraction of molecules having kinetic energy less than Ea.(B) At a given temperature, lower the Ea , faster is the reaction.(C) Increase in temperature by about $10^{\circ} C$ doubles the rate of reaction.(D) Plot of $log k$ vs $\frac{1}{T}$ gives a straight line with slope $= - \frac{Ea}{R}$ .
Choose the correct answer from the options given below:
1. (1) $(B) and (D) Only$
2. (2) $(A) and (B) Only$
3. (3) $(B) and (C) Only$
4. (4) $(A) and (C) Only$
274.
Consider the reaction carried out at $T (K)$
$A (g) + B (g) \to C (g)$
The rate law for this reaction is $r = k [A]^{1} [B]^{2}$ . The concentration of $A$ in experiment 2 and rate in experiment 3 shown as $x$ and $z$ in the table, $x$ and $z$ are respectively
Experiment
$\frac{[ A ]}{mol L ^{- 1}}$
$\frac{[ B ]}{mol L ^{- 1}}$
Initial rate
$(mol L^{- 1} s^{- 1)})$

1
0.05
0.05
$R$
2
$x$
0.05
$2 R$
3
0.20
0.10
$z$
1. (1) $x = 0.10 z = 8 R$
2. (2) $x = 0.05 z = 4 R$
3. (3) $x = 0.10 z = 16 R$
4. (4) $x = 0.20 z = 16 R$
275.
It is true that
1. (1) $A zero order reaction is a single step reaction$
2. (2) $A zero order reaction is a multistep reaction$
3. (3) $A first order reaction is always a single step reaction$
4. (4) $A second order reaction is always a multistep reaction$
276.
In a reaction, $A + B \to$ product, rate is doubled when the concentration of $B$ is doubled, and rate increases by a factor of 8 when the concentration of both the reactants ( $A$ and $B$ ) are doubled, rate law for the reaction can be written as
1. (1) $rate = k [A] [B]^{2}$
2. (2) $rate = k [A]^{2} [B]^{2}$
3. (3) $rate = k [A] [B]$
4. (4) $rate = k [A]^{2} [B]$
277.
For the reaction $A + B \to$ products, it is observed that(i) on doubling the initial concentration of $A$ only the rate of reaction is also doubled and (ii) on doubling the initial concentration of both $A$ and $B$ , there is a change by a factor of 8 in the rate of the reaction.The rate of this reaction is given by
1. (1) $rate = k [A] [B]^{2}$
2. (2) $rate = k [A]^{2} [B]^{2}$
3. (3) $rate = k [A] [B]$
4. (4) $rate = k [A]^{2} [B]$
278.
Which one of the following given graphs represents the variation of rate constant (k) with temperature (T) for an endothermic reaction ?
1. (1)
2. (2)
3. (3)
4. (4)
279.
For a given reaction $R \to P, t_{1/2}$ is related to $[A]_{0}$ as given in table. Given: $log 2 = 0.30$ Which of the following is true? A. The order of the reaction is $1/2$ . B. If $[A]_{0}$ is 1 M , then $t_{1/2}$ is $20010 min C$ . The order of the reaction changes to 1 if the concentration of reactant changes from 0.100 M to 0.500 M. D. $t_{1/2}$ is 800 min for $[A]_{0} = 1.6 M$ Choose the correct answer from the options given below: Options
1. (1) $A and C Only$
2. (2) $A, B and D Only$
3. (3) $C and D Only$
4. (4) $A and B Only$
280.
Identify the intermediate in the following sequence of reaction. $2 SO_{2} + 2 NO_{2} \to 2 SO_{3} + 2 NO 2 NO + O_{2} \to 2 NO_{2}$
1. (1) $SO_{2}$
2. (2) $SO_{3}$
3. (3) $NO_{2}$
4. (4) $NO$
281.
When a biochemical reaction is carried out in laboratory, outside the human body in absence of enzyme, then rate of reaction obtained is $1 0^{- 6}$ times, the activation energy of reaction in the presence of enzyme is
1. (1) $6/ R T$
2. (2) $P is required$
3. (3) $different from E_{a} obtained in laboratory$
4. (4) $can’t say anything.$
282.
For the reaction, $2 A + B \to 3 C + D$ , which ofthe following does not express the reaction rate?
1. (1) $- \frac{d [ A ]}{2 d t}$
2. (2) $- \frac{d [ C ]}{3 d t}$
3. (3) $-$
4. (4) $\frac{d [ D ]}{d t}$
283.
In a zero‐order reaction, for every $1 0^{0} C$ rise of temperature, the rate is doubled. If the temperature is increased from $1 0^{0} C$ to $10 0^{o} C,$ the rate of the reaction will become
1. (1) $256 times$
2. (2) $512 times$
3. (3) $64 times$
4. (4) $128 times$
284.
A reaction is 50% complete in 2 hours and 75% complete in 4 hours. The order of reaction is
1. (1) $1$
2. (2) $2$
3. (3) $3$
4. (4) $0$
285.
$A student has studied the decomposition of a gas A B_{3} at 25°C. He obtained the following data.$
$p(mm Hg)$ $50$ $100$ $200$ $400$
$Relative t_{1/2} (s)$ $4$ $2$ $1$ $0.5$
$The order of the reaction is$
1. (1) $0.5$
2. (2) $2$
3. (3) $1$
4. (4) $0$
286.
The reaction takes place in two steps as
(i) $NO_{2} Cl_{(g)} \to K_{1} NO_{2 (g)} + Cl_{(g)}$
(ii) $NO_{2} Cl_{(g)} + Cl_{(g)} \to K_{2} NO_{2 (g)} + Cl_{(g)}$
Identify the reaction intermediate.
1. (1) $NO_{2} Cl_{(g)}$
2. (2) $Cl_{2 (g)}$
3. (3) $NO_{2 (g)}$
4. (4) $Cl_{(g)}$
287.
$Pre-exponential factors of two different reactions of same order are identical. Let activation energy of first reaction exceeds the activation energy of second reaction by 20 kJ mol^{- 1} . If k_{1} and k_{2} are the rate constants of first and second reaction respectively at 300 K , then ln \frac{k _{2}}{k _{1}} will be____. (nearest integer) (R = 8.3 J K^{- 1} mol^{- 1})$
288.
$A ⟶ B (first reaction) C ⟶ D (second reaction) Consider the above two first-order reactions. The rate constant for first reaction at 500 K is double of the same at 300 K. At 500 K, 50 % of the reaction becomes complete in 2 hour. The activation energy of the second reaction is half of that of first reaction. If the rate constant at 500 K of the second reaction becomes double of the rate constant of first reaction at the same temperature; then rate constant for the second reaction at 300 K is____\times 10^{- 1} hour^{- 1} (nearest integer).$
289.
$NO_{2} required for a reaction is produced by decomposition of N_{2} O_{5} in CCl_{4} as by equation 2 N_{2} O_{5 (g)} \to 4 NO_{2} (g) + O_{2} (g) The initial concentration of N_{2} O_{5} is 3 mol L^{- 1} and it is 2.75 mol L^{- 1} after 30 minutes. The rate of formation of NO_{2} is x \times 10^{- 3} mol L^{- 1} min^{- 1}, value of x is_______$
290.
$Consider the following single step reaction in gas phase at constant temperature. 2 A_{(g)} + B_{(g)} \to C_{(g)} The initial rate of the reaction is recorded as r_{1} when the reaction starts with 1.5 atm pressure of A and 0.7 atm pressure of B . After some time, the rate r_{2} is recorded when the pressure of C becomes 0.5 atm . The ratio r_{1} : r_{2} is ______\times 10^{- 1} . (Nearest integer)$
291.
$Consider A k_{1} B and C k_{2} D are two reactions. If the rate constant (k_{1}) of the A ⟶ B reaction can be expressed by the following equation log_{10} k = 14.34 - \frac{1.5 \times 10 ^{4}}{T / K} and activation energy of C ⟶ D reaction (E a_{2}) is \frac{1}{5} th of the A ⟶ B reaction (E a_{1}), then the value of (E a_{2}) is____kJmol^{- 1} . (Nearest Integer)$
292.
$For the thermal decomposition of N_{2} O_{5} (g) at constant volume, the following table can be formed, for the reaction mentioned below. 2 N_{2} O_{5} (g) \to 2 N_{2} O_{4} (g) + O_{2} (g) Sr.No Time/s Total pressure/(atm) 10 0.6 2100 ‘X’ x = \dots \times 10^{- 3} atm [nearest integer] Given: Rate constant for the reaction is 4.606 \times 10^{- 2} s^{- 1} .$
293.
$N_{2} O_{5 (g)} \to 2N O_{2 (g)} + \frac{1}{2} O_{2 (g)} In the above first order reaction the initial concentration of N_{2} O_{5} is 2.40 \times 1 0^{- 2} mol L^{- 1} at 318 K. The concentration of N_{2} O_{5} after 1 hour was 1.60 \times 1 0^{- 2} mol L^{- 1} . The rate constant of the reaction at 318 K is ____\times 1 0^{- 3} min^{- 1} . (Nearest integer) [Given : log 3 = 0.477, log 5 = 0.699]$
294.
$For a reversible reaction A ⇌ B, the Δ H of forward reaction = 20 kJ m o l^{- 1} . The activation energy of the uncatalyzed forward reaction is 300 kJ m o l^{- 1} . When the reaction is catalysed keeping the reactant concentration same, the rate of the catalysed forward reaction at 27°C is found to be same as that of the uncatalyzed reaction at 327°C. The activation energy of the catalysed backward reaction is ____ kJ m o l^{- 1} .$
295.
$For a first order reaction A \to B, the rate constant, k = 5. 5 x 1 0^{- 14} V. The time required for 67% completion of reaction is x \times 1 0^{- 1} times the half life of reaction. The value of x is ________(Nearest integer)(Given: log 3 = 0.4771)$
296.
$The equation k = (6. 5 x 1 0^{12} s^{- 1}) e^{- 26000 K / T} is followed for the decomposition of compound A. The activation energy for the reaction is ____ kJ m o l^{- 1} . [nearest integer](Given: R = 8.314 J K^{- 1} m o l^{- 1})$
297.
$[A] \to [B] Reactant Product If formation of compound [B] follows the first order of kinetics and after 70 minutes the concentration of [A] was found to be half of its initial concentration. Then the rate constant of the reaction is x \times 1 0^{- 6} s^{- 1} . The value of x is______.(Nearest Integer)$
298.
$Assuming 1 μ g of trace radioactive element X with a half life of 30 years is absorbed by a growing tree. The amount of X remaining in the tree after 100 years is___x10^{- 1} μ g [Given : In 10 = 2.303; log2 = 0.30]$
299.
$For a first order reaction, the ratio of the time for 75% completion of a reaction to the time for 50% completion is ____. (Integer answer)$
300.
$For certain chemical reaction X \to Y, the rate of formation of product is plotted against the time as shown in the figure. The number of Correct statement/s from the following is_______(A) Over all order of this reaction is one (B) Order of this reaction can't be determined (C) In region-I and III, the reaction is of first and zero order respectively (D) In region-11, the reaction is of first order (E) In region-11, the order of reaction is in the range of 0.1 to 0.9.$