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13
MCQ (Single Correct Answer)

Which of the following graphs represents exothermic reaction?

A
Only (I)
B
Only (II)
C
Only (III)
D
(I) and (III)
14
MCQ (Single Correct Answer)

Rate law for the reaction $\mathrm{A}+2 \mathrm{~B} \longrightarrow \mathrm{C}$ is found to be

$$\text { Rate }=k[A][B]$$

Concentration of reactant ' B ' is doubled, keeping the concentration of ' A ' constant, the value of rate constant will be ............... .

A
the same
B
doubled
C
quadrupled
D
halved
15
MCQ (Single Correct Answer)

Which of the following statements is incorrect about the collision theory of chemical reaction?

A
It considers reacting molecules or atoms to be hard spheres and ignores their structural features
B
Number of effective collisions determines the rate of reaction
C
Collision of atoms or molecules possessing sufficient threshold energy results into the product formation
D
Molecules should collide with sufficient threshold energy and proper orientation for the collision to be effective
16
MCQ (Single Correct Answer)

A first order reaction is $50 \%$ completed in $1.26 \times 10^{14} \mathrm{~s}$. How much time would it take for $100 \%$ completion?

A
$1.26 \times 10^{15} \mathrm{~s}$
B
$2.52 \times 10^{14} \mathrm{~s}$
C
$2.52 \times 10^{28} \mathrm{~s}$
D
Infinite
17
MCQ (Single Correct Answer)
 

Compounds ' $A$ ' and ' $B$ ' react according to the following chemical equation.

$$\mathrm{A}(\mathrm{~g})+2 \mathrm{~B}(\mathrm{~g}) \longrightarrow 2 \mathrm{C}(\mathrm{~g})$$

Concentration of either ' $A$ ' or ' $B$ ' were changed keeping the concentrations of one of the reactants constant and rates were measured as a function of initial concentration. Following results were obtained. Choose the correct option for the rate equations for this reaction.

Expereiment Initial
concentration of
[A]/mol L$^{-1}$		 Initial
concentration of
[B]/mol L$^{-1}$		 Initial
concentration of
[C]/mol L$^{-1}$ S$^{-1}$
1. 0.30 0.30 0.10
2. 0.30 0.60 0.40
3. 0.60 0.30 0.20

A
Rate $=k[A]^2[B]$
B
Rate $=k[A][B]^2$
C
Rate $=k[A][B]$
D
Rate $=k[A]^2[B]^0$
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