Chemical Kinetics PYQs Set 4 (PDF)

Set 4 of 11 · Questions 91-120 of 311

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Mere Teacher · Previous Year Questions JEE Main Chemistry · Chemical Kinetics · Set 4 (Q91-120)
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91. $Integrated rate law equation for a first order gas phase reaction is given by (where P_{i} is initial pressure and P_{t} is total pressure at time t)$ (1) $k = \frac{2.303}{t} \times log \frac{P _{i}}{( 2 P _{i} - P _{t} )}$ (2) $k = \frac{2.303}{t} \times log \frac{2 P _{i}}{( 2 P _{i} - P _{t} )}$ (3) $k = \frac{2.303}{t} \times log \frac{( 2 P _{i} - P _{t} )}{P _{i}}$ (4) $k = \frac{2.303}{t} \times \frac{P _{i}}{( 2 P _{i} - P _{t} )}$ 92. $In which one of the following reactions, rate constant has the unit mol L^{- 1} s^{- 1} ?$ (1) $Acid catalysed hydrolysis of CH_{3} COOCH_{3}$ (2) $CHCl_{3} + Cl_{2} ⟶ CCl_{4} + HCl$ (3) $2 NO_{(g)} + O_{2 (g)} ⟶ 2 NO_{2 (g)}$ (4) $Decomposition of HI on the surface of gold$ 93. $A bacterial infection in an internal wound grows as N’ (t) = N_{0} exp (t), where the time t is in hours. A dose of antibiotic, taken orally, needs 1 hour to reach the wound. Once it reaches there, the bacterial population goes down as \frac{dN}{dt} = - 5 N^{2} . What will be the plot of \frac{N _{0}}{N} vs. t after 1 hour ?$ (1) (2) (3) (4) 94. $The half-life for a zero order reaction having 0.02 M initial concentration of reactant is 100 s . The rate constant (in mol L^{- 1} s^{- 1}) for the reaction is$ (1) $2.0 \times 10^{- 4}$ (2) $2.0 \times 10^{- 3}$ (3) $1.0 \times 10^{- 2}$ (4) $1.0 \times 10^{- 4}$ 95. $What is the value of rate constant for first order reaction if slope for the graph of rate versus concentration is 2.5 \times 10^{- 3} ?$ (1) $2.5 \times 10^{- 3} time^{- 1}$ (2) $5.0 \times 10^{- 3} time^{- 1}$ (3) $7.5 \times 10^{- 3} time^{- 1}$ (4) $1.25 \times 10^{- 3} time^{- 1}$ 96. $Decomposition of X exhibits a rate constant of 0.05 μg / year. How many years are required for the decomposition of 5 μg of X into 2.5 μg ?$ (1) $50$ (2) $25$ (3) $20$ (4) $40$ 97. $In a first order decomposition reaction, the time taken for the decomposition of reactant to one fourth and one eighth of its initial concentration are t_{1} and t_{2} (s), respectively. The ratio t_{1} / t_{2} will be:$ (1) $\frac{4}{3}$ (2) $\frac{3}{2}$ (3) $\frac{3}{4}$ (4) $\frac{2}{3}$ 98. $If the rate of the reaction is equal to the rate constant, the order of the reaction is$ (1) $0$ (2) $1$ (3) $2$ (4) $3$ 99. $Which of the following is a zero order reaction?$ (1) $2 HI \to H_{2} + I_{2}$ (2) $H_{2} + B r_{2} Δ 2 H B r$ (3) $2 N_{2} O_{5} \to 4 NO_{2} + O_{2}$ (4) $H_{2} + Cl_{2} \to hv 2 HCl$ 100. $In the first order thermal decomposition of C_{2} H_{5} I (g) \to C_{2} H_{4} (g) + HI (g), the reactant in the beginning exerts a pressure of 2 bar in a closed vessel at 600 K . If the partial perssure of the reactant is 0.1 bar after 1000 minutes at the same temperature the rate constant in min^{- 1} is (log 2 = 0.3010)$ (1) $6.0 \times 10^{- 4}$ (2) $6.0 \times 10^{- 3}$ (3) $3.0 \times 10^{- 3}$ (4) $3.0 \times 10^{- 4}$ 101. $Half life of zero order reaction A \to product is 1 hour, when initial concentration of reactant is 2.0 mol L^{- 1} . The time required to decrease concentration of A from 0.50 to 0.25 mol L^{- 1} is:$ (1) $0.5 hour$ (2) $15 min$ (3) $60 min$ (4) $4 hour$ 102. $If the equilibrium constant for A ⇌ B + C is K_{eq}^{(1)} and that of B + C ⇌ P is K_{eq}^{(2)} the equilibrium constant for A ⇌ P is$ (1) $K_{eq}^{(1)} / K_{eq}^{(2)}$ (2) $K_{eq}^{(1)} + K_{eq}^{(2)}$ (3) $K_{eq}^{(2)} - K_{eq}^{(1)}$ (4) $K_{eq}^{(1)} K_{eq}^{(2)}$ 103. $For the chemical reaction N_{2} (g) + 3 H_{2} (g) ⇌ 2 NH_{3} (g) The correct option is:$ (1) $- \frac{1}{3} \frac{d ( H _{2} )}{dt} = - \frac{1}{2} \frac{d ( NH _{3} )}{dt}$ (2) $- \frac{d ( N _{2} )}{dt} = 2 \frac{d ( NH _{3} )}{dt}$ (3) $- \frac{d ( N _{2} )}{dt} = \frac{1}{2} \frac{d ( NH _{3} )}{dt}$ (4) $3 \frac{d ( H _{2} )}{dt} = 2 \frac{d ( NH _{3} )}{dt}$ 104. $For the reaction 2 A + B \to C, the values of initial rate at different reactant concentration are given in the table below. The rate law for the reaction is : [A] (mol L^{- 1}) [B] (mol L^{- 1}) Initial Rate (mol L^{- 1} s^{- 1}) 0.05 0.05 0.045 0.10 0.05 0.090 0.20 0.10 0.72$ (1) $Rate = k (A) (B)^{2}$ (2) $Rate = k (A)^{2} (B)^{2}$ (3) $Rate = k (A) (B)$ (4) $Rate = k (A)^{2} (B)$ 105. $The first order decomposition of in an appropriate medium is characterised by a rate constant of 0.2303 . What is the time (in ) required to complete fraction of the reaction?$ (1) $0.1$ (2) $10$ (3) $100$ (4) $0.01$ 106. $The rate constant for a first order reaction is 4.606 \times 10^{- 3} s^{- 1} . The time required to reduce 2.0 g of the reactant to 0.2 g is:$ (1) $200 s$ (2) $500 s$ (3) $1000 s$ (4) $100 s$ 107. $For the reaction A + B \to C, the following data were obtained Exp Initial concentration Initial rate [A] M [B] M (M min^{- 1}) 1. 0.1 0.1 1.0 \times 10^{- 4} 2. 0.1 0.3 9.0 \times 10^{- 4} 3. 0.3 0.3 2.7 \times 10^{- 3} The order of reaction with respect to A and B are respectively$ (1) $1,2$ (2) $2,1$ (3) $1.5, 1.5$ (4) $0,3$ 108. $The rate of a certain biochemical reaction at physiological temperature (T) occurs 10^{6} times faster with enzyme than without. The change in the activation energy upon adding enzyme is:$ (1) $- 6 \times 2.303 RT$ (2) $+ 6 \times 2.303 RT$ (3) $+ 6 RT$ (4) $- 6 RT$ 109. $The activation energy of a reaction is zero, Its rate constant at 280 K is 1.6 \times 10^{- 6} s^{- 1}, the rate constant at 300 K is$ (1) $3.2 \times 10^{- 6} s^{- 1}$ (2) $1.6 \times 10^{- 6} s^{- 1}$ (3) $zero$ (4) $1.6 \times 10^{- 5} s^{- 1}$ 110. $100 cm^{3} of 1 MCH_{3} COOH was mixed with 100 cm^{3} of 2 M CH_{3} OH to form an ester. The change in the initial rate if each solution is diluted with equal volume of water would be$ (1) $4 times$ (2) $0.25 times$ (3) $2 times$ (4) $0.5 times.$ 111. $An organic compound undergoes first order decomposition. The time taken for decomposition to (\frac{1}{8})^{th} and (\frac{1}{10})^{th} of its initial concentration are t_{1/8} and t_{1/10} respectively. What is the value of \frac{t _{1/8}}{t _{1/10}} \times 10 ? (log 2 = 0.3)$ (1) $3$ (2) $9$ (3) $0.9$ (4) $30$ 112. $Half-life of a reaction is found to be inversely proportional to the fifth power of its initial concentration, the order of reaction is$ (1) $5$ (2) $6$ (3) $3$ (4) $4$ 113. $If the definition of the temperature coefficient of the reaction holds good for a reaction between 27^{\circ} C and 37^{\circ} C, the activation energy for the reaction in kJ / mol^{- 1} is$ (1) $102$ (2) $53.5$ (3) $\infty$ (4) $141.5$ 114. $Find the rate law for the reaction, CHCl_{3 (g)} + Cl_{2 (g)} \to CCl_{4 (g)} + HCl_{(g)} if order of reaction with respect to CHCl_{3 (g)} is one and 1/2 with Cl_{2 (g)} .$ (1) $Rate = k (CHCl_{3}) (Cl_{2})^{1/2}$ (2) $Rate = k (CHCl_{3})^{2} (Cl_{2})^{1/2}$ (3) $Rate = k (CHCl_{3})^{3/2} (Cl_{2})$ (4) $Rate = k (CHCl_{3})^{1/2} (Cl_{2})$ 115. $The reaction A \to B follows first order kinetics. The time taken for 0.8 mole of A to produce 0.6 mole o f B is 1 hour. What is the time taken for conversion of 0.9 mole of A to produce 0.675 mole of B ?$ (1) $1 hour$ (2) $0.5 hour$ (3) $0.25 hour$ (4) $2 hours$ 116. $Which of the following statement is not true for radioactive decay?$ (1) $Decay constant increases with increase in temperature.$ (2) $Amount of radioactive substance remained after three half lives is \frac{1}{8} th of original amount.$ (3) $Decay constant does not depend upon temperature.$ (4) $Half life is ln 2 times of \frac{1}{rate constant}$ 117. $The half-life of^{65} Zn is 245 days. After x days, 75 % of original activity remained. The value of x in days is____. (Nearest integer) (Given: log 3 = 0.4771 and log 2 = 0.3010)$ 118. $The reaction 2 A + B_{2} \to 2 AB is an elementaryreaction. For a certain quantity of reactants, if the volumeof the reaction vessel is reduced by a factor of 3the rate of the reaction increases by a factor of ____. (Roundoff to the Nearest Integer).$ 119. $If the activation energy of a reaction is , the fraction of molecules at 700 K having enoughenergy to react to form products is . The value of is ____. (Rounded off to the nearest integer)$ 120. $The temperature at which the rate constants of the given below two gaseous reactions become equal is____K. (Nearest integer) X \to Y, k_{1} = 10^{6} e^{\frac{- 30000}{T}} P ⟶ Q, k_{2} = 10^{4} e^{\frac{- 24000}{T}} Given: ln 10 = 2.303$