Chemical Kinetics PYQs Set 4 (PDF)

Set 4 of 8 · Questions 91-120 of 224

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Mere Teacher · Previous Year Questions NEET Chemistry · Chemical Kinetics · Set 4 (Q91-120)
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91. $The activation energy of a reaction is zero, Its rate constant at 280 K is 1.6 \times 10^{- 6} s^{- 1}, the rate constant at 300 K is$ (1) $3.2 \times 10^{- 6} s^{- 1}$ (2) $1.6 \times 10^{- 6} s^{- 1}$ (3) $zero$ (4) $1.6 \times 10^{- 5} s^{- 1}$ 92. $100 cm^{3} of 1 MCH_{3} COOH was mixed with 100 cm^{3} of 2 M CH_{3} OH to form an ester. The change in the initial rate if each solution is diluted with equal volume of water would be$ (1) $4 times$ (2) $0.25 times$ (3) $2 times$ (4) $0.5 times.$ 93. $An organic compound undergoes first order decomposition. The time taken for decomposition to (\frac{1}{8})^{th} and (\frac{1}{10})^{th} of its initial concentration are t_{1/8} and t_{1/10} respectively. What is the value of \frac{t _{1/8}}{t _{1/10}} \times 10 ? (log 2 = 0.3)$ (1) $3$ (2) $9$ (3) $0.9$ (4) $30$ 94. $Half-life of a reaction is found to be inversely proportional to the fifth power of its initial concentration, the order of reaction is$ (1) $5$ (2) $6$ (3) $3$ (4) $4$ 95. $If the definition of the temperature coefficient of the reaction holds good for a reaction between 27^{\circ} C and 37^{\circ} C, the activation energy for the reaction in kJ / mol^{- 1} is$ (1) $102$ (2) $53.5$ (3) $\infty$ (4) $141.5$ 96. $Find the rate law for the reaction, CHCl_{3 (g)} + Cl_{2 (g)} \to CCl_{4 (g)} + HCl_{(g)} if order of reaction with respect to CHCl_{3 (g)} is one and 1/2 with Cl_{2 (g)} .$ (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) $Rate = k (CHCl_{3})^{1/2} (Cl_{2})$ 97. $The reaction A \to B follows first order kinetics. The time taken for 0.8 mole of A to produce 0.6 mole o f B is 1 hour. What is the time taken for conversion of 0.9 mole of A to produce 0.675 mole of B ?$ (1) $1 hour$ (2) $0.5 hour$ (3) $0.25 hour$ (4) $2 hours$ 98. $Which of the following statement is not true for radioactive decay?$ (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) $Half life is ln 2 times of \frac{1}{rate constant}$ 99. $Which among the following reactions is an example of pseudo-first order reaction?$ (1) $Inversion of cane sugar$ (2) $Decomposition of H_{2} O_{2}$ (3) $Conversion of cyclopropane to propene$ (4) $Decomposition of N_{2} O_{5}$ 100. $For n^{th} order of reaction, half-life period is directly proportional to$ (1) $a^{n - 1}$ (2) $a^{1 - n}$ (3) $none of the above$ (4) $1 a^{1 - n}$ 101. $The activation energy for a reaction at the temperature T K was found to be 2.303 RT J mol^{- 1} . The ratio of the rate constant to Arrhenius factor is$ (1) $10^{- 1}$ (2) $10^{- 2}$ (3) $2 \times 10^{- 3}$ (4) $2\times 1 0^{- 2}$ 102. $The activation energy of a chemical reaction can be determined by$ (1) $evaluating rate constants at two different temperatures$ (2) $changing the concentration of reactants$ (3) $evaluating the concentration of reactants at two different temperatures$ (4) $evaluating rate constant at standard temperature.$ 103. $The rate constants k_{1} and k_{2} for two different reactions are 10^{16} \times e^{- 2000/ T} and 10^{15} \times e^{- 1000/ T} respectively. The temperature at which k_{1} = k_{2} is$ (1) $\frac{2000}{2.303} K$ (2) $2000 K$ (3) $\frac{1000}{2.303} K$ (4) $1000 K$ 104. $Find the correct equation among the following.$ (1) $ln k - ln A = \frac{E _{a}}{RT}$ (2) $k = \frac{A E _{a}}{RT}$ (3) $ln k + ln A = \frac{E _{a}}{RT}$ (4) $\frac{E _{a}}{RT} = ln A - ln k$ 105. $If the rate constant for a first order reaction is 2.303 \times 10^{- 3} s^{- 1} . Find the time required to reduce 4 g of the reactant to 0.2 g .$ (1) $1.30 hours$ (2) $21.60 hours$ (3) $0.36 hours$ (4) $2.60 hours$ 106. $Time required for 100 percent completion of a zero order reaction is$ (1) $\frac{2 k}{a}$ (2) $\frac{a}{2 k}$ (3) $\frac{a}{k}$ (4) $ak$ 107. $A_{(g)} \to Δ P_{(g)} + Q_{(g)} + R_{(g)}, follows first order kinetics with a half-life of 69.3 s at 500^{\circ} C . Starting from the gas ' A' enclosed in a container at 500^{\circ} C and at a pressure of 0.4 atm, the total pressure of the system after 230 s will be$ (1) $1.15 atm$ (2) $1.32 atm$ (3) $1.22 atm$ (4) $1.12 atm$ 108. $A (g) \to B (g) + C (g) is a first order reaction. Time t \infty P_{system} P_{t} P_{\infty} The reaction was started with reactant A only. Which of the following expressions is correct for rate constant k ?$ (1) $k = \frac{1}{t} ln \frac{p _{\infty}}{p _{t}}$ (2) $k = \frac{1}{t} ln \frac{p _{\infty}}{2 ( p _{\infty} - p _{t} )}$ (3) $k = \frac{1}{t} ln \frac{2 ( p _{\infty} - p _{t} )}{p _{t}}$ (4) $k = \frac{1}{t} ln \frac{p _{\infty}}{( p _{\infty} - p _{t} )}$ 109. $If 50 % of the reactant is converted into a product in a first order reaction in 25 minutes, how much of it would react in 100 minutes?$ (1) $93.75 %$ (2) $87.5 %$ (3) $75 %$ (4) $100 %$ 110. $The rate constant for a first order reaction is 7.0 \times 10^{- 4} s^{- 1} . If initial concentration of reactant is 0.080 M, what is the half life of reaction?$ (1) $990 s$ (2) $79.2 s$ (3) $12375 s$ (4) $10.10 \times 10^{- 4} s$ 111. $For a zero-order reaction, the correct expression for rate constant (k) at half-life time (t_{1/2}) is (R_{0} =) initial concentration of reactant)$ (1) $k = \frac{2.303}{t _{1/2}} log \frac{( R _{0} )}{\frac{( R _{0} )}{2}}$ (2) $k = \frac{2.303}{t} log \frac{( R _{0} )}{( R _{0} )}$ (3) $k = \frac{( R _{0} ) - \frac{1}{2} ( R _{0} )}{t _{1/2}}$ (4) $k = \frac{2.303}{( t _{2} - t _{1} )} log (R_{0})$ 112. $Drug X becomes ineffective after 50 % decomposition. The original concentration of drug in a bottle was 16 mg / mL which becomes 4 mg / mL in 12 months. The expiry time of the drug in months is Assume that the decomposition of the drug follows first order kinetics.$ (1) $2$ (2) $6$ (3) $12$ (4) $3$ 113. $The rate of reaction increases with rise in temperature because of$ (1) $increase in number of activated molecules$ (2) $increase in energy of activation$ (3) $decrease in energy of activation$ (4) $none of the above$ 114. $The concentration of a reactant X decreases from 0.1 M to 0.005 M in 40 minutes. If the reaction follows I order kinetics, the rate of the reaction when the concentration of X is 0.01 M will be$ (1) $1.73 \times 10^{- 4} M min^{- 1}$ (2) $3.47 \times 10^{- 4} M min^{- 1}$ (3) $3.47 \times 10^{- 5} M min^{- 1}$ (4) $7.5 \times 10^{- 4} M min^{- 1}$ 115. $A given sample of milk turns sour at room temperature (27^{\circ} C) in 5 hours. In a refrigerator at - 3^{\circ} C, it can be stored 10 times longer. The energy of activation for the souring of milk is$ (1) $2.303 \times 10 R kJ mol^{- 1}$ (2) $2.303 \times 5 R kJ mol^{- 1}$ (3) $2.303 \times 3 R k J mol^{- 1}$ (4) $2.303 \times 2.7 R k J mol^{- 1}$ 116. $For A_{2} + B_{2} ⇌ 2 AB E_{a} for forward and backward reaction are 180 and 200 kJ mol^{- 1} respectively If catalyst lowers E_{a} for both reaction by 100 kJ mol^{- 1} . Which of the following statement is correct?$ (1) $Catalyst does not alter the Gibbs energy change of a reaction.$ (2) $The enthalpy change for the reaction is + 20 kJ mol^{- 1} .$ (3) $Catalyst can cause non-spontaneous reactions to occur.$ (4) $The enthalpy change for the catalyzed reaction is different from that of uncatalyzed reaction.$ 117. $For a reaction A \to B, enthalpy of reaction is - 4.2 kJ mol^{- 1} and enthalpy of activation is 9.6 kJ mol^{- 1} . The correct potential energy profile for the reaction is shown in option.$ (1) (2) (3) (4) 118. $A first order reaction has a specific reaction rate of 1 0^{- 2} se c^{- 1} . How much time will it take for 20 g of the reactant to reduce to 5 g ?$ (1) $138.6 sec$ (2) $346.5 sec$ (3) $693.0 sec$ (4) $238.6 sec$ 119. $Average rate of reaction 2 SO_{2 (g)} + O_{2 (g)} ⟶ 2 SO_{3 (g)}, is written as$ (1) $\frac{Δ ( SO _{2} )}{Δ t}$ (2) $- \frac{Δ ( O _{2} )}{Δ t}$ (3) $\frac{1}{2} \frac{Δ ( SO _{2} )}{Δ t}$ (4) $\frac{Δ ( SO _{3} )}{Δ t}$ 120. $The rate of the reaction: CH_{3} COOC_{2} H_{5} + NaOH \to CH_{3} COONa + C_{2} H_{5} OH is given by the equation Rate = k (CH_{3} COOC_{2} H_{5}) [NaOH] If concentration is expressed in mol L^{- 1}, the unit of k is$ (1) $Lmol -1 s^{- 1}$ (2) $mol^{- 2} L2 s^{- 1}$ (3) $s^{- 1}$ (4) $molL-1 s^{- 1}$