Chemical Kinetics PYQs Set 9 (PDF)

Set 9 of 11 · Questions 241-270 of 311

In the print window choose “Save as PDF”. The file prints without a web address or date line.

Mere Teacher · Previous Year Questions JEE Main Chemistry · Chemical Kinetics · Set 9 (Q241-270)
Scan or visit mereteacher.com for free PYQ practice, timed CBT tests, step-by-step solutions and BroBot AI. Answers and solutions are free with a sign-up.
241. $For bacterial growth in a cell culture, growth law is very similar to the law of radioactive decay. Which of the following graphs is most suitable to represent bacterial colony growth? Where N - Number of Bacteria at any time, N_{0} - Initial number of Bacteria.$ (1) (2) (3) (4) 242. $Consider the given figure and choose the correct option:$ (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) $Activation energy of forward reaction is E_{1} + E_{2} and product is more stable than reactant.$ 243. $The rate constant (k) of a reaction is measured at different temperatures (T), and the data are plotted in the given figure. The activation energy of the reaction in kJ mol^{- 1} is (R is gas constant)$ (1) $1/ R$ (2) $2/ R$ (3) $2 R$ (4) $R$ 244. $The correct difference between first and second order reactions is that$ (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) $the rate of a first‐order reaction does depend on reactant concentrations; the rate of a second‐order reaction does not depend on reactant concentrations$ 245. $For a reaction, consider the plot of ln k versus 1/T given in the figure. If the rate constant of this reaction at 400 K is 10^{- 5} s^{- 1}, then the rate constant at 500 K is:$ (1) $10^{- 6} s^{- 1}$ (2) $2 \times 10^{- 1} s^{- 1}$ (3) $10^{- 4} s^{- 1}$ (4) $4 \times 10^{- 4} s^{- 2}$ 246. $The given plots represents the variation of the concentration of a reactant R with time for two different reactions (i) and (ii). The representive orders of the reactions are :$ (1) $1, 0$ (2) $1, 1$ (3) $0, 1$ (4) $0, 2$ 247. $Which of the following graphs most appropriately represents a zero order reaction?$ (1) (2) (3) (4) 248. $In the reaction, BrO_{3 (a q)}^{-} + 5 Br_{(a q)}^{-} + 6 H^{+} \to 3 Br_{2 (l)} + 3 H_{2} O_{(l)} . The rate of appearance of bromine (^{B r}) is related to rate of disappearance of bromide ions as$ (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) $\frac{d [ B r _{2} ]}{d t} = - \frac{3}{5} \frac{d [ B r ^{-} ]}{d t}$ 249. $For an elementary reaction, 2 A + 3 B \to 4 C + D the rate of appearance of C at time t is 2.8 \times 1 0^{- 3} mol L^{- 1} s^{- 1} . Rate of disappearance of B at time t will be$ (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) $\frac{4}{3} (2.8 \times 1 0^{- 3}) mol L^{- 1} s^{- 1}$ 250. $The rate constant, k for a first order reaction, C_{2} H_{5} I (g) \to C_{2} H_{4} (g) + H I (g) is x s^{- 1} at 600 K and 4 x s^{- 1} at 700 K . The energy of activation of the reaction (in k J m o l^{- 1}) is$ (1) $48.16$ (2) $58.16$ (3) $38.16$ (4) $28.16$ 251. $For the non-stoichiometric reaction: 2 A + B \to C + D, the following kinetic data were obtained in three separate experiments, all at 298 K . Initial concentration [A] Initial concentration [B] Initial rate of formation of C ( mol L (^{- 1} s^{- 1}) 0.1 M 0.1 M 1.2 \times 10^{- 3} 0.1 M 0.2 M 1.2 \times 10^{- 3} 0.2 M 0.1 M 2.4 \times 10^{- 3} The rate law for the formation of C is$ (1) $\frac{dC}{dt} = k [A]$ (2) $\frac{dC}{dt} = k [A] [B]$ (3) $\frac{dC}{dt} = k [A]^{2} [B]$ (4) $\frac{dC}{dt} = k [A] [B]^{2}$ 252. $Observe the following reactions at T (K) . (I) A \to products. (II) 5 Br^{-} (aq) + BrO_{3}^{-} (aq) + 6 H^{+} (aq) \to 3 Br_{2} (aq) + 3 H_{2} O (l) Both the reactions are started at 10.00 am. The rates of these reactions at 10.10 am are same. The value of - \frac{Δ ( Br ^{-} )}{Δ t} at 10.10 am is 2 \times 10^{- 4} mol L^{- 1} min^{- 1} . The concentration of A at 10.10 am is 10^{- 2} mol L^{- 1} . What is the first order rate constant (in min^{- 1}) of reaction I ?$ (1) $10^{- 2}$ (2) $10^{- 3}$ (3) $2\times 1 0^{- 3}$ (4) $4\times 1 0^{- 3}$ 253. $Consider the following statements related to temperature dependence of rate constants. Identify the correct statements.(A) The Arrhenius equation holds true only for an elementary homogenous reaction.(B) The unit of A is same as that of k in Arrhenius equation.(C) At a given temperature, a low activation energy means a fast reaction.(D) A and Ea as used in Arrhenius equation depend on temperature.(E) When Ea ≫ RT, A and Ea become interdependent. Choose the correct answer from the options given below:$ (1) $A, C and D Only$ (2) $B, D and E Only$ (3) $B and C Only$ (4) $A and B Only$ 254. $The first order rate constant for the decomposition of C a C O_{3} at 700K is 6. 36 x 1 0^{- 3} s^{- 1} and activation energy is 209kJ m o l^{- 1} . Its rate constant (in s^{- 1}) at 600K is x \times 1 0^{- 6} . The value of x is ____. (Nearest integer) [Given R = 8.31 J K^{- 1} m o l^{- 1}; log 6.36 \times 1 0^{- 3} = -2.19, 1 0^{- 4.79} = 1.62 \times 1 0^{- 5}]$ 255. $For the reaction A \to B the following graph was obtained. The time required (in seconds) for the concentration of A to reduce to 2.5 g L^{- 1} (if the initial concentration of A was 50 g L^{- 1}) is . (Nearest integer) Given: lo g 2 = 0.3010$ 256. $2NO + 2 H_{2} \to N_{2} + 2 H_{2} O The above reaction has been studied at 800°C. The related data are given in the table below Reaction serial number Initial pressure of H_{2} / kPa Initial Pressure of NO/ kPa Initial rate 1 65.6 40.0 0.135 2 65.6 20.1 0.033 3 38.6 65.6 0.214 4 19.2 65.6 0.106 The order of the reaction with respect to NO is____$ 257. $The rate constants for decomposition of acetaldehyde have been measured over the temperature range 700 -1000 K. The data has been analysed by plotting In k vs \frac{1 0 ^{3}}{T} graph. The value of activation energy for the reaction is___kJ m o l^{- 1} . (Nearest integer) (Given : R = 8.31 J K^{- 1} m o l^{- 1})$ 258. $The number of correct statement/s from the following is_______. A. Larger the activation energy, smaller is the value of the rate constant. B. The higher is the activation energy, higher is the value of the temperature coefficient. C. At lower temperatures, increase in temperature causes more change in the value of k than at higher temperature. D. A plot of ln k vs \frac{1}{T} is a straight line with slope equal to - \frac{E a}{R}$ 259. $For the thermal decomposition of reactant AB (g), the following plot is constructed. The half-life of the reaction is ' x^{’} min . x =____min. (Nearest integer)$ 260. $For a given chemical reaction γ_{1} A + γ_{2} B \to γ_{3} C + γ_{4} D Concentration of C changes from 10 mmol d m^{- 3} to 20 mmol d m^{- 3} in 10 seconds. Rate of appearance of D is 1.5 times the rate of disappearance of B which is twice the rate of disappearance A. The rate of appearance of D has been experimentally determined to be 9 mmol d m^{- 3} s^{- 1} . Therefore the rate of reaction is ________mmol d n r^{3} s^{- l} . (Nearest Integer)$ 261. $For the reaction A \to B, the rate constant k (in s^{- 1}) is given by lo g_{10} k = 20.35 - \frac{( 2.47 \times 1 0 ^{3} )}{T} The energy of activation in kJ m o l^{- 1} is ____. (Nearest integer) [Given :R = 8.314 J K^{- 1} m o l^{- 1}]$ 262. $The activation energy of one of the reactions in a biochemical process is 532611 J m o l^{- l} . When the temperature falls from 310 K to 300 K, the change in rate constant observed is k_{30} o= x x 1 0^{- 3} k_{310} . The value of x is _________. [Given: ln10 = 2.3 R=8. 3 J K^{- 1} m o l^{- 1}]$ 263. $The reaction 2NO + B r_{2} \to 2 NOBr takes place through the mechanism given below NO + B r_{2} N O B r_{2} (fast) N O B r_{2} + NO \to 2 NOBr (slow) The overall order of the reaction is_____.$ 264. $t_{87} ._{5} is the time required for the reaction to undergo 87.5% completion and t_{50} is the time required for the reaction to undergo 50% completion. The relation between t_{87.5} and t_{50} for a first order reaction is t_{87.5} = x \times t_{50} The value 01 x is__________. (Nearest integer)$ 265. $It has been found that for a chemical reaction with rise in temperature by 9K the rate constant gets doubled. Assuming a reaction to be occurring at 300 K, the value of activation energy is found to be ______kJ m o l^{- 1} . [nearest integer] (Given In 10 = 2.3, R = 8.3 J K^{- 1} W^{- 1}, Iog2 = 0.30)$ 266. $Sucrose hydrolyses in acid solution into glucose and fructose following first order rate law with a half-life of 3.33 h at 25°C. After 9 h, the fraction of sucrose remaining is . The value of is ____ (Rounded off to the nearest integer) [Assume: , ]$ 267. $During the nuclear explosion, one of the products is^{90} Sr with half life of 6.93 years. If 1 μg of it was absorbed in the bones of a newly born baby in place of Ca, how much time, in years, is required to reduce it by 90% if it is not lost metabolically.$ 268. $A \to B The molecule A changes into its isomeric form B by following a first order kinetics at a temperature of 1000 K. If the energy barrier with respect to reactant energy for such isomeric transformation is 191.48 kJ mol^{- 1} and the frequency factor is 10^{20}, the time required for 50 % molecules of A to become B is picoseconds (nearest integer). [(R = 8.314 J K^{- 1} mol^{- 1})$ 269. $2 NO (g) + Cl_{2} (g) ⇌ 2 NOCl (s) This reaction was studied at -10°C and thefollowing data was obtained run (NO)_{0} (C l_{2})_{0} r_{0} 1 0.10 0.10 0.18 2 0.10 0.20 0.35 3 0.20 0.20 1.40 (NO)_{0} and (C l_{2})_{0} are the initial concentrations and is the initial reaction rate.The overall order of thereaction is____.(Round off to the Nearest Integer)$ 270. $Consider the following first order gas phase reaction at constant temperature A (g) \to 2 B (g) + C (g) If the total pressure of the gases is found to be 200 torr after 23 sec . and 300 torr upon the complete decomposition of A after a very long time, then the rate constant of the given reaction is \times 10^{- 2} s^{- 1} (nearest integer) [Given : log_{10} (2) = 0.301]$