Chemical Kinetics PYQs Set 5 (PDF)

Set 5 of 8 · Questions 121-150 of 224

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Mere Teacher · Previous Year Questions NEET Chemistry · Chemical Kinetics · Set 5 (Q121-150)
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121. $Which among the following equations represents Arrhenius equation?$ (1) $k = A e^{E_{a} / RT}$ (2) $k = A e^{RT / E_{a}}$ (3) $k = \frac{A}{e ^{E_{a} / RT}}$ (4) $k = \frac{A}{e ^{RT / E_{a}}}$ 122. $The given reaction, 2 F e C 1_{3} + S n C l_{2} \to 2 F e C l_{2} + S n C l_{4} is an example of$ (1) $third order reaction$ (2) $first order reaction$ (3) $second order reaction$ (4) $none of these$ 123. $Slope of the straight line obtained by plotting log_{10} k against 1/ T represents what term?$ (1) $- E_{a}$ (2) $- 2.303 E_{a} / R$ (3) $- E_{a} /2.303 R$ (4) $- E_{a} / R$ 124. $For a certain reaction, the rate = k [A]^{2} [B] . When the initial concentration of A is tripled keeping concentration of B constant, the initial rate would$ (1) $increase by a factor of three.$ (2) $decrease by a factor of nine.$ (3) $increase by a factor of six.$ (4) $increase by a factor of nine$ 125. $The relationship between rate constant and half-life period of zero order reaction is given by$ (1) $t_{1/2} = [A]_{0} 2 k$ (2) $t_{1/2} = \frac{0.693}{k}$ (3) $t_{1/2} = \frac{[ A ] _{0}}{2 k}$ (4) $t_{1/2} = \frac{2 [ A ] _{0}}{k}$ 126. $The following data is obtained during the first order thermal decomposition of 2 A_{(s)} ⟶ B_{(s)} + C_{(s)} at constant volume and temperature. S. No. Time Total pressure in Pascal 1. At the end of 10 minutes 300 2. After completion 200 The rate constant in min^{- 1} is$ (1) $0.0693$ (2) $6.93$ (3) $0.00693$ (4) $69.3$ 127. $For a chemical reaction A \to B, the rate of the reaction is 2 \times 10^{- 3} mol dm^{- 3} s^{- 1}, when the initial concentration is 0.05 mol dm^{- 3} . The rate of the same reaction is 1.6 \times 10^{- 2} mol dm^{- 3} s^{- 1} when the initial concentration is 0.1 moldm^{- 3} . The order of the reaction is$ (1) $0$ (2) $3$ (3) $1$ (4) $2$ 128. $In a reaction A + B \to C, initial concentrations of A and B are related as [A]_{0} = 8 [B]_{0} . The half lives of A and B are 10 min and 40 min, respectively. If they start to disappear at the same time, both following first order kinetics, after how much time will the concentration of both the reactants be same?$ (1) $20 min$ (2) $40 min$ (3) $80 min$ (4) $60 min$ 129. $For a chemical reaction, mA \to xB, the rate law is r = k [A]^{2} . If the concentration of A is doubled, the reaction rate will be$ (1) $doubled$ (2) $quadrupled$ (3) $increased by 8 times$ (4) $unchanged.$ 130. $The rate constant of a reaction is given by k = PZ e^{- E_{a} / RT} under standard notation. In order to speed up the reaction, which of the following factors has to be decreased?$ (1) $Both Z and T$ (2) $E_{a}$ (3) $T$ (4) $Z$ 131. $For the reaction, A_{2} + B + C \to AC + AB, it is found that tripling the concentration of A_{2} triples the rate, doubling the concentration of C doubles the rate and doubling the concentration of B has no effect. What is the rate law?$ (1) $k (A_{2})^{2} [C]$ (2) $k [B]^{1/2} [C]$ (3) $k (A_{2}) [C]$ (4) $k (A_{2})^{3} [B]^{2} [C]$ 132. $A possible mechanism for the gaseous reaction 2 H_{2} + 2 NO \to 2 H_{2} O + N_{2} is Step 1: 2 NO ⇌ N_{2} O_{2} Step 2: N_{2} O_{2} + H_{2} \to N_{2} O + H_{2} O (slow) Step 3: N_{2} O + H_{2} \to N_{2} + H_{2} O The rate law for this :eaction is$ (1) $R = k [NO]^{2} (H_{2})^{2}$ (2) $R = k [NO] (H_{2})^{2}$ (3) $R = k [NO]^{1/2} (H_{2})$ (4) $R = k [NO]^{2} (H_{2})$ 133. $The following results were obtained during kinetic studies of the reaction; 2 A + B \to Products Experiment [A] (in mol L^{- 1}) [B] (in mol L^{- 1}) Initial Rate of reaction (in mol L^{- 1} min^{- 1}) I 0.10 0.20 6.93 \times 10^{- 3} II 0.10 0.25 6.93 \times 10^{- 3} III 0.20 0.30 1.386 \times 10^{- 2} The time (in minutes) required to consume half of A is :$ (1) $5$ (2) $10$ (3) $1$ (4) $100$ 134. $What is the concentration (in mol L^{- 1}) of the product after 20 s in the following reaction. Given that A \to 3 B, rate = k [A]^{\circ} Time(s) Concentration of the reactant (mol L^{- 1}) 0 0.1 15 0.05 20 0.1 - x$ (1) $6.6 \times 10^{- 2}$ (2) $1.32 \times 10^{- 1}$ (3) $1.98 \times 10^{- 1}$ (4) $2.2 \times 10^{- 2}$ 135. $Rate constants in the following reaction are Reaction 1: A \to catalyst 1 P_{1}, k_{1} = 1 s^{- 1} Reaction 2 : A \to catalyst 2 P_{2}, k_{2} = 0.1 L mol^{- 1} s^{- 1} Reaction 3 : A \to catalyst 3 P_{3}, k_{3} = 0.01 L^{2} mol^{- 2} s^{- 1} The correct relations between the rate of the reactions at 1 M of A are$ (1) $r_{1} = \frac{r _{3}}{100}, r_{2} = \frac{r _{3}}{10}$ (2) $r_{1} = \frac{r _{2}}{10}, r_{2} = \frac{r _{3}}{10}$ (3) $r_{1} = 100 r_{3}, r_{2} = \frac{r _{3}}{10}$ (4) $r_{1} = 10 r_{2}, r_{3} = \frac{r _{2}}{10}$ 136. $Calculate the rate constant of the first order reaction if 80 % of the reactant decomposes in 60 minutes.$ (1) $2.68 \times 10^{- 2} minute^{- 1}$ (2) $5.36 \times 10^{- 2} minute^{- 1}$ (3) $1.34 \times 10^{- 2} minute^{- 1}$ (4) $8.1 \times 10^{- 2} minute^{- 1}$ 137. $Temperature coefficient of a reaction is ' 2 '. When temperature is increased from 30^{\circ} C to 90^{\circ} C, the rate of reaction is increased by$ (1) $60 times$ (2) $64 times$ (3) $150 times$ (4) $400 times.$ 138. $The decomposition of phosphine (_{3}^{P H}) on tungsten at low pressure is a first‐order reaction. It is because the$ (1) $rate is proportional to the surface coverage$ (2) $rate is inversely proportional to the surface coverage$ (3) $rate is independent of the surface coverage$ (4) $rate of decomposition is very slow.$ 139. $Chemical reactions with very high E_{a} values are generally$ (1) $very fast$ (2) $very slow$ (3) $moderately fast$ (4) $spontaneous.$ 140. $For the decomposition of a compound AB at 600 K, the following data were obtained [AB] mol dm^{- 3} Rate of decomposition of AB in mol dm 0.20 2.75 \times 10^{- 8} 0.40 11.0 \times 10^{- 8} 0.60 24.75 \times 10^{- 8} The order for the decomposition of AB is$ (1) $0$ (2) $1$ (3) $2$ (4) $1.5$ 141. $If the following reaction : xA \to yB = log_{10} (- \frac{d ( A )}{dt}) = log_{10} (\frac{d ( B )}{dt}) + 0.3010 ‘A’ and ‘B’ respectively can be:$ (1) $n - Butane and Iso-butane$ (2) $C_{2} H_{2} and C_{6} H_{6}$ (3) $C_{2} H_{4} and C_{4} H_{8}$ (4) $N_{2} O_{4} and N O_{2}$ 142. $Rate law for the reaction, A + B \to product is rate = k ((A)^{2} [B]) . What is the rate constant, if rate of reaction at a given temperature is 0.22 M s^{- 1}, when [A] = 1 M and [B] = 0.25 M ?$ (1) $3.52 M^{- 2} s^{- 1}$ (2) $1.136 M^{- 2} s^{- 1}$ (3) $0.88 M^{- 2} s^{- 1}$ (4) $0.05 M^{- 2} s^{- 1}$ 143. $The rate constant, k of a zero order reaction 2 NH_{3} (g) \to Pt 1130 k N_{2} (g) + 3 H_{2} (g) is y \times 10^{- 4} mol L^{- 1} s^{- 1} . The rate of formation of hydrogen (in mol L^{- 1} s^{- 1}) is$ (1) $y \times 10^{- 4}$ (2) $2y\times 1 0^{- 4}$ (3) $3y\times 1 0^{- 4}$ (4) $y3\times 1 0^{- 4}$ 144. $For the reaction, 2 SO_{2} + O_{2} ⇌ 2 SO_{3}, the rate of disappearance of O_{2} is 2 \times 10^{- 4} mol L^{- 1} s^{- 1} . The rate of appearance of SO_{3} is$ (1) $2 \times 10^{- 4} mol L^{- 1} s^{- 1}$ (2) $4 \times 10^{- 4} mol L^{- 1} s^{- 1}$ (3) $1 \times 10^{- 1} mol L^{- 1} s^{- 1}$ (4) $6 \times 10^{- 4} mol L^{- 1} s^{- 1}$ 145. $The graph obtained between ln k (k = Rate constant) on y -axis 1/ T on x -axis is a straight line. The slope of it is - 4 \times 10^{4} k . The activation energy of the reaction (in kJ mol^{- 1})is (R = 8.3 J K^{- 1} mol^{- 1})$ (1) $166$ (2) $332$ (3) $765$ (4) $382$ 146. $The activation energy for a simple chemical reaction A ⇌ B is E_{a} in forward direction. The activation energy for reverse reaction$ (1) $is negative of E_{a}$ (2) $is always less than E_{a}$ (3) $can be less than or more than E_{a}$ (4) $is always double of E_{a} .$ 147. $For a reaction, A + B \to Products, the rate of the reaction at various concentrations are given below : Expt No [A] [B] rate (mol dm^{- 3} s^{- 1}) 1 0.2 0.2 22 0.2 0.4 43 0.6 0.4 36 The rate law for the above reaction is$ (1) $r = k [A]^{2} [B]$ (2) $r = k [A]^{3} [B]$ (3) $r = k [A] [B]^{2}$ (4) $r = k [A]^{2} [B]^{2}$ 148. $When the temperature of a reaction is raised by 10^{\circ} C, how many times the rate will be enhanced?$ (1) $1.5$ (2) $3$ (3) $2$ (4) $4$ 149. $In the reaction, A \to products, If the concentration of the reactant is doubled rate of the reaction remains unchanged. The order of the reaction with respect to A is$ (1) $1$ (2) $2$ (3) $0.5$ (4) $0$ 150. $The rate of chemical reaction doubles with every 10^{\circ} C rise in temperature. If the reaction is carried out in the vicinity of 22^{\circ} C, the activation energy of the reaction is (given R = 8.3 J K^{- 1} mol^{- 1}, ln 2 = 0.69 and ln 3 = 1.1)$ (1) $1.69 kJ mol^{- 1}$ (2) $0.169 kJ mol^{- 1}$ (3) $49.8 kJ mol^{- 1}$ (4) $498 J mol^{- 1}$