NEET Chemistry Chemical Kinetics Questions Solved

NEET - 2010

During the kinetic Study of the reaction, 2A+B→C+D, following results were obtained

Run   [A]/mol L-1  [B]/mol L-1      Initial rate of formation of D/mol L-1 min-1
I          0.1                 0.1                6.0x10-3
II         0.3                 0.2                7.2x10-2
III        0.3                 0.4                2.88x10-1
IV        0.4                 0.1                2.40x10-2

Based on the above data which one of the following is correct ?

(a)  rate=k[A]2[B]
(b)  rate=k[A][B]
(c)  rate=k[A]2[B]2
(d) rate=k[A][B]2

Let the order of reaction with respect to A is x and with respect to B is y. Thus, rate= k[A]x [B]y
For the given cases,
(I) rate= k(0.1)x (0.1)y=6.0x10-3
(II) rate= k(0.3)x (0.2)y=7.2x10-2
(III) rate= k(0.3)x (0.40)y=2.88x10-1
(IV) rate= k(0.4)x (0.1)y=2.40x10-2

On dividing eq. (II) by (III), we get
(0.3/0.3)x (0.2/0.4)y = 7.2X10-2/2.88X10-1
or (1/2)y=1/4
or (1/2)y=(1/2)2

Thus, rate law is, rate= k[A]1[B]2 or =k[A][B]2

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