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JEE Main 20199 JanuaryMorning Shift
Exam
JEE Main
Year
2019
Date
9 January
Shift
Morning Shift
Subject
Chemistry
Chapter
Chemical Kinetics

JEE Main 2019 · 9 January · Morning Shift · Chemistry · Chemical Kinetics

The following results were obtained during kinetic studies of the...

The following results were obtained during kinetic studies of the reaction.

2A+B→2A + B \to product
Experiment \left[A\right] \left(inmolL^{- 1}\right)</td><td>[B](inmolL−1)</td> <td> \left[B\right] \left(inmolL^{- 1}\right) Initial rate of reaction \left(inmolL^{- 1}min{}^{- 1}\right)</td></tr><tr><td></td> </tr> <tr> <td>I</td><td></td> <td>0. 10</td><td></td> <td>0. 20</td><td></td> <td>6.93 \times {10}^{- 3}</td></tr><tr><td></td> </tr> <tr> <td>II</td><td></td> <td>0. 10</td><td></td> <td>0. 25</td><td></td> <td>6.93 \times {10}^{- 3}</td></tr><tr><td></td> </tr> <tr> <td>III</td><td></td> <td>0. 20</td><td></td> <td>0. 30</td><td></td> <td>1.386 \times {10}^{- 2}</td></tr></tbody></table><br/>Thetime(inminutes)requiredtoconsumehalfof</td> </tr> </tbody></table><br />The time (in minutes) required to consume half of\text{A}isis

Options

  1. A100100
  2. B1010
  3. C55
  4. D11

Correct answer

B. 1010

Step-by-step solution

Let's assume xandyx and y are the order of the reaction with respect to AandBA and B, respectively.

From equation (1)\left(1\right) and (2)\left(2\right),

(0.10.1)x(0.20.25)y=6.93×10−36.93×10−3⇒y=0{\left(\dfrac{0 .1}{0 .1}\right)}^{x}{\left(\dfrac{0 .2}{0 .25}\right)}^{y} = \dfrac{6 .93 \times {10}^{- 3}}{6 .93 \times {10}^{- 3}} ⇒ y = 0

From equation \left(1\right)andand\left(3\right)andputthevalueand put the valuey = 0,<br/><br/>,<br /><br />{\left(\dfrac{0 .1}{0 .2}\right)}^{x}{\left(\dfrac{0 .2}{0 .3}\right)}^{0} = \dfrac{6 .93 \times {10}^{- 3}}{1 .386 \times {10}^{- 2}} ∴ y = 0<br/><br/><br /><br />{\left(\dfrac{1}{2}\right)}^{x} = \left(\dfrac{1}{2}\right) ⇒ x = 1<br/><br/>Theratelawwillbe<br /><br />The rate law will beR = K{[ A ]}^{1}{[ B ]}^{0}<br/><br/>Hence,thereactionisofthefirstorder.<br/><br/><br /><br />Hence, the reaction is of the first order.<br /><br />K = \dfrac{R}{\left[A\right]} = \dfrac{6 .93 \times {10}^{- 3}}{0 .1} = 6 .93 \times {10}^{- 2}<br/><br/>Here<br /><br />Heret\dfrac{1}{2}forthefirst−orderreactionisgivenby,for the first-order reaction is given by,t\dfrac{1}{2} = \dfrac{0 .693}{K} = \dfrac{0 .693}{( 6 .93 \times {10}^{- 2})} =10
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