Chemical Kinetics PYQs Set 7 (PDF)

Set 7 of 8 · Questions 181-210 of 224

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Mere Teacher · Previous Year Questions NEET Chemistry · Chemical Kinetics · Set 7 (Q181-210)
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181. $When initial concentration of a reactant is doubled in a reaction, its half‐life period is not affected. The order of the reaction is$ (1) $second$ (2) $more than zero but less than first$ (3) $zero$ (4) $first.$ 182. $Which from following is the slope of the graph of rate versus concentration of the reactant for first order reaction?$ (1) $- k$ (2) $k$ (3) $\frac{k}{2.303}$ (4) $- k 2.303$ 183. $Mechanism of a hypothetical reaction X_{2} + Y_{2} \to 2 X Y, is given below: (i) X_{2} \to X + X (fast) (ii) X + Y_{2} \Leftrightarrow X Y + Y (slow) (iii) X + Y \to X Y (fast) The overall order of the reaction will be$ (1) $2$ (2) $0$ (3) $1.5$ (4) $1$ 184. $If 60% of a first order reaction was completed in 60 minutes, 50% ofthe same reaction would be completed in approximately (lo g 4 = 0.60, lo g 5 = 0.69)$ (1) $45 minutes$ (2) $60 minutes$ (3) $40 minutes$ (4) $50 minutes$ 185. $Consider the following reaction that goes from A to B in three steps as shown below: Choose the correct option Number of Intermediates Number of Activated Complexes Rate determining step 123 I 223 III 323 II 432 II$ (1) $(a)$ (2) $(b)$ (3) $(c)$ (4) $(d)$ 186. $Half‐life period of a first order reaction is 1386 seconds. The specific rate constant of the reaction is$ (1) $0. 5 \times 1 0^{- 2} s^{- 1}$ (2) $0. 5 \times 1 0^{- 3} s^{- 1}$ (3) $5. 0 \times 1 0^{- 2} s^{- 1}$ (4) $5. 0 \times 1 0^{- 3} s^{- 1} .$ 187. $The given graph is a representation of kinetics of a reaction. The y and x axes for zero and first order reactions, respectively are$ (1) $zero order (y= rate and x = c oncentration ), first order ( y= rate and x = t_{1/2})$ (2) $zero order (y= concentration and x= time ), first order y = t_{1/2} and x = c concentration )$ (3) $zero order (y= concentration and x= time ), first order ( y= rate constant and x = c oncentration)$ (4) $zero order ( y= rate and x= concentration), first order (y = t_{1/2} and x= concentration)$ 188. $For a zero order reaction A \to product, a plot of [A] (on y-axis) and time (on x -axis) gave a straight line with slope equal to - 3 \times 10^{- 3} M min^{- 1} and intercept equal to 2 \times 10^{- 2} M (on y-axis). What is the rate constant (in M min^{- 1}) of this reaction?$ (1) $3 \times 10^{- 3}$ (2) $5 \times 10^{- 5}$ (3) $3 \times 10^{- 4}$ (4) $5 \times 10^{- 4}$ 189. $Consider the following plots of log of rate constant k (log k) vs \frac{1}{T} for three different reactions. The correct order of activation energies of these reactions is:$ (1) $Ea_{2} > Ea_{1} > Ea_{3}$ (2) $Ea_{1} > Ea_{3} > Ea_{2}$ (3) $Ea_{3} > Ea_{2} > Ea_{1}$ (4) $Ea_{1} > Ea_{2} > Ea_{3}$ 190. $For bacterial growth in a cell culture, growth law is very similar to the law of radioactive decay. Which of the following graphs is most suitable to represent bacterial colony growth? Where N - Number of Bacteria at any time, N_{0} - Initial number of Bacteria.$ (1) (2) (3) (4) 191. $Consider the given figure and choose the correct option:$ (1) $Activation energy of both forward and backward reaction is E_{1} + E_{2} and reactant is more stable than product.$ (2) $Activation energy of forward E_{1} + E_{2} and and product is less stable than reactant.$ (3) $Activation energy of backward reaction is E_{1} and product is more stable than reactant.$ (4) $Activation energy of forward reaction is E_{1} + E_{2} and product is more stable than reactant.$ 192. $The rate constant (k) of a reaction is measured at different temperatures (T), and the data are plotted in the given figure. The activation energy of the reaction in kJ mol^{- 1} is (R is gas constant)$ (1) $1/ R$ (2) $2/ R$ (3) $2 R$ (4) $R$ 193. $The correct difference between first and second order reactions is that$ (1) $the rate of a first‐order reaction does not depend on reactant concentrations; the rate of a second‐order reaction does depend on reactant concentrations$ (2) $the half‐life of a first‐order reaction does not depend on [A]_{0}; the half‐life of a second‐ order reaction does depend on [A]_{0}$ (3) $a first‐order reaction can be catalysed; a second‐order reaction cannot be catalysed$ (4) $the rate of a first‐order reaction does depend on reactant concentrations; the rate of a second‐order reaction does not depend on reactant concentrations$ 194. $For a reaction, consider the plot of ln k versus 1/T given in the figure. If the rate constant of this reaction at 400 K is 10^{- 5} s^{- 1}, then the rate constant at 500 K is:$ (1) $10^{- 6} s^{- 1}$ (2) $2 \times 10^{- 1} s^{- 1}$ (3) $10^{- 4} s^{- 1}$ (4) $4 \times 10^{- 4} s^{- 2}$ 195. $The given plots represents the variation of the concentration of a reactant R with time for two different reactions (i) and (ii). The representive orders of the reactions are :$ (1) $1, 0$ (2) $1, 1$ (3) $0, 1$ (4) $0, 2$ 196. $Which of the following graphs most appropriately represents a zero order reaction?$ (1) (2) (3) (4) 197. $In the reaction, BrO_{3 (a q)}^{-} + 5 Br_{(a q)}^{-} + 6 H^{+} \to 3 Br_{2 (l)} + 3 H_{2} O_{(l)} . The rate of appearance of bromine (^{B r}) is related to rate of disappearance of bromide ions as$ (1) $\frac{d [ B r _{2} ]}{d t} = - \frac{5}{3} \frac{d [ B r ^{-} ]}{d t}$ (2) $\frac{d [ B r _{2} ]}{d t} = \frac{5}{3} \frac{d [ B r ^{-} ]}{d t}$ (3) $\frac{d [ B r _{2} ]}{d t} = \frac{3}{5} \frac{d [ B r ^{-} ]}{d t}$ (4) $\frac{d [ B r _{2} ]}{d t} = - \frac{3}{5} \frac{d [ B r ^{-} ]}{d t}$ 198. $For an elementary reaction, 2 A + 3 B \to 4 C + D the rate of appearance of C at time t is 2.8 \times 1 0^{- 3} mol L^{- 1} s^{- 1} . Rate of disappearance of B at time t will be$ (1) $\frac{3}{4} (2.8 \times 1 0^{- 3}) mol L^{- 1} s^{- 1}$ (2) $2 (2.8 \times 1 0^{- 3}) mol L^{- 1} s^{- 1}$ (3) $\frac{1}{4} (2.8 \times 1 0^{- 3}) mol L^{- 1} s^{- 1}$ (4) $\frac{4}{3} (2.8 \times 1 0^{- 3}) mol L^{- 1} s^{- 1}$ 199. $The rate constant, k for a first order reaction, C_{2} H_{5} I (g) \to C_{2} H_{4} (g) + H I (g) is x s^{- 1} at 600 K and 4 x s^{- 1} at 700 K . The energy of activation of the reaction (in k J m o l^{- 1}) is$ (1) $48.16$ (2) $58.16$ (3) $38.16$ (4) $28.16$ 200. $For the non-stoichiometric reaction: 2 A + B \to C + D, the following kinetic data were obtained in three separate experiments, all at 298 K . Initial concentration [A] Initial concentration [B] Initial rate of formation of C ( mol L (^{- 1} s^{- 1}) 0.1 M 0.1 M 1.2 \times 10^{- 3} 0.1 M 0.2 M 1.2 \times 10^{- 3} 0.2 M 0.1 M 2.4 \times 10^{- 3} The rate law for the formation of C is$ (1) $\frac{dC}{dt} = k [A]$ (2) $\frac{dC}{dt} = k [A] [B]$ (3) $\frac{dC}{dt} = k [A]^{2} [B]$ (4) $\frac{dC}{dt} = k [A] [B]^{2}$ 201. $Observe the following reactions at T (K) . (I) A \to products. (II) 5 Br^{-} (aq) + BrO_{3}^{-} (aq) + 6 H^{+} (aq) \to 3 Br_{2} (aq) + 3 H_{2} O (l) Both the reactions are started at 10.00 am. The rates of these reactions at 10.10 am are same. The value of - \frac{Δ ( Br ^{-} )}{Δ t} at 10.10 am is 2 \times 10^{- 4} mol L^{- 1} min^{- 1} . The concentration of A at 10.10 am is 10^{- 2} mol L^{- 1} . What is the first order rate constant (in min^{- 1}) of reaction I ?$ (1) $10^{- 2}$ (2) $10^{- 3}$ (3) $2\times 1 0^{- 3}$ (4) $4\times 1 0^{- 3}$ 202. $Consider the following statements related to temperature dependence of rate constants. Identify the correct statements.(A) The Arrhenius equation holds true only for an elementary homogenous reaction.(B) The unit of A is same as that of k in Arrhenius equation.(C) At a given temperature, a low activation energy means a fast reaction.(D) A and Ea as used in Arrhenius equation depend on temperature.(E) When Ea ≫ RT, A and Ea become interdependent. Choose the correct answer from the options given below:$ (1) $A, C and D Only$ (2) $B, D and E Only$ (3) $B and C Only$ (4) $A and B Only$ 203. $A person's wound was exposed to some bacteria and then bacterial growth started to happen at the same place. The wound was later treated with some antibacterial medicine and the rate of bacterial decay(r) was found to be proportional with the square of the existing number of bacteria at any instance. Which of the following set of graphs correctly represents the 'before' and 'after' situation of the application of the medicine? [Given: N = No. of bacteria, t = time, bacterial growth follows 1^{st} order kinetics.]$ (1) (2) (3) (4) 204. $The results given in the below table were obtained during kinetic studies of the following reaction 2 A + B \to C + D 2 A + B \to C + D x and Y in the given table are respectively Experiment [A] / molL^{- 1} [B] / molL^{- 1} Initial rate molL^{- 1} min^{- 1} I 0.1 0.1 6.00 \times 10^{- 3} II 0.1 0.2 2.40 \times 10^{- 2} III 0.2 0.1 1.20 \times 10^{- 2} IV X 0.2 7.20 \times 10^{- 2} V 0.3 Y 2.88 \times 10^{- 1}$ (1) $0.4, 0.3$ (2) $0.3, 0.4$ (3) $0.4, 0.4$ (4) $0.3, 0.3$ 205. $Correct statements regarding Arrhenius equation among the following are :(A) Factor corresponds to fraction of molecules having kinetic energy less than Ea.(B) At a given temperature, lower the Ea , faster is the reaction.(C) Increase in temperature by about doubles the rate of reaction.(D) Plot of vs gives a straight line with slope .Choose the correct answer from the options given below:$ (1) $(B) and (D) Only$ (2) $(A) and (B) Only$ (3) $(B) and (C) Only$ (4) $(A) and (C) Only$ 206. $Consider the reaction carried out at T (K) A (g) + B (g) \to C (g) The rate law for this reaction is r = k [A]^{1} [B]^{2} . The concentration of A in experiment 2 and rate in experiment 3 shown as x and z in the table, x and z are respectively Experiment \frac{[ A ]}{mol L ^{- 1}} \frac{[ B ]}{mol L ^{- 1}} Initial rate (mol L^{- 1} s^{- 1)}) 1 0.05 0.05 R 2 x 0.05 2 R 3 0.20 0.10 z$ (1) $x = 0.10 z = 8 R$ (2) $x = 0.05 z = 4 R$ (3) $x = 0.10 z = 16 R$ (4) $x = 0.20 z = 16 R$ 207. $It is true that$ (1) $A zero order reaction is a single step reaction$ (2) $A zero order reaction is a multistep reaction$ (3) $A first order reaction is always a single step reaction$ (4) $A second order reaction is always a multistep reaction$ 208. $In a reaction, A + B \to product, rate is doubled when the concentration of B is doubled, and rate increases by a factor of 8 when the concentration of both the reactants (A and B) are doubled, rate law for the reaction can be written as$ (1) $rate = k [A] [B]^{2}$ (2) $rate = k [A]^{2} [B]^{2}$ (3) $rate = k [A] [B]$ (4) $rate = k [A]^{2} [B]$ 209. $For the reaction A + B \to products, it is observed that(i) on doubling the initial concentration of A only the rate of reaction is also doubled and (ii) on doubling the initial concentration of both A and B, there is a change by a factor of 8 in the rate of the reaction.The rate of this reaction is given by$ (1) $rate = k [A] [B]^{2}$ (2) $rate = k [A]^{2} [B]^{2}$ (3) $rate = k [A] [B]$ (4) $rate = k [A]^{2} [B]$ 210. $Which one of the following given graphs represents the variation of rate constant (k) with temperature (T) for an endothermic reaction ?$ (1) (2) (3) (4)