NEET Chemistry Chemical Kinetics Questions Solved

BOARD

(a) The decomposition of A into products has a value of K as 4.5 $×$10s-1 at ${10}^{\circ }$ C and energy of activation 60 KJ mol-1. At what temperature would K be 1.5 $×$ ?

(b)  (i) If half life period of a first order reaction is $\mathcal{x}$ and 3/4th life period of the same reaction is y, how are x and y related to each other ?

(ii) In some cases it is found that a large number  of colloiding molecules have energy more than threshold energy, yet the reaction is slow, Why?

(a) given : K1 = 4.5 $×$ 103 s-1,

T1 = 10K + 273K =283K

K2 = 1.5 $×$ 104 s-1,     T2 =?

Ea = 60 KJ mol-1

Using formula :

$\therefore$  Temperatue, Twill be =

=${24}^{\circ }$C

(b) (i) t1/2 =$\frac{0.693}{K}$   (For first order reaction)

t3/4 =K           $⇒$t3/4 =$\frac{1.3864}{K}$

According to condition

(The value 1.3864 is double of 0.693)

From the above equation it is clear that

(ii) It is due to improper orientation of the colloiding molecules at the time of collision.

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