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6.

The following data were  obtained for a given reaction at 300K

Reaction                             Energy of activation(kJ mol-1)

(i) uncatalysed                             76

(ii)  catalysed                              57

the factor by which rate of catalysed reaction is increased , is

A) 21

B) 2100

C) 2000

D) 1200

7.

A reaction: A2+B → products, involves the following mechanism

$A_{2}\rightleftharpoons 2A$  (fast)

(a being the intermediate)

A+B  $\overrightarrow{k_{2}}$  Products (slow)   The rate law consistent to this mechanism is

A) $rate =k[A_{2}][B]$

B) $rate =k[A_{2}]^{2}[B]$

C) $rate =k[A_{2}]^{1/2}[B]$

D) $rate =k[A_{2}][B]^{2}$

8.

In a reaction, A→ Products, when start is made from 80 x 10-2 M of A, the half-life is found to be 120 minutes. For the initial concentration  4.0 x 10-2 M  , the half-life of the reaction becomes 240 minutes. The order of the reaction is

A) 0

B) 1

C) 2

D) 0.5

9.

A plot In K against $\frac {1}{T}$ (abscissa) is expected to be a straight line with intercept  on ordinate axis equal to

A) $\frac{\triangle S^{0}}{2.303 R}$

B) $\frac{\triangle S^{0}}{ R}$

C) -$\frac{\triangle S^{0}}{ R}$

D) $\triangle S^{0}\times R$

10.

A moles of PCl5 is heated in a closed container to equilibrium   $PCl_{5}\rightleftharpoons PCl_{3}(g)+ Cl_{2}(g)$ at a pressure of p  atm. If x moles of PCl5 disscociate at equilibrium  , then

A) $\frac{x}{a}=\frac{K_{p}}{K_{p}+P}$

B) $\frac{x}{a}=\left(\frac{K_{p}+P}{K_{p}}\right)^{1/2}$

C) $\frac{x}{a}=\left(\frac{K_{p}}{P}\right)^{1/2}$

D) $\frac{x}{a}=\left(\frac{K_{p}}{K_{p}+P}\right)^{1/2}$

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