For the reaction N2O5(g) $$ \to $$ 2NO2(g) + 1/2O2(g) the value of rate of disappearance of N2O5 is given as 6.25 $$ \times $$ 10$$-$$3 mol L$$-$$1 s$$-$$1. The rate of formation of NO2 and O2 is given respectively as
Half-life period of a first order reaction is 1386 seconds. The specific rate constant of the reaction is
A
0.5 $$ \times $$ 10$$-$$2 s$$-$$1
B
0.5 $$ \times $$ 10$$-$$3 s$$-$$1
C
5.0 $$ \times $$ 10$$-$$2 s$$-$$1
D
5.0 $$ \times $$ 10$$-$$3 s$$-$$1.
Explanation
Specific rate constant
k = $${{0.693} \over {{t_{1/2}}}}$$
= $${{0.693} \over {1386}}$$
= 0.5 $$ \times $$ 10-3 sec-1
3
AIPMT 2009
MCQ (Single Correct Answer)
For the reaction A + B $$ \to $$ products, it is observed that
(i) on doubling the initial concentration of A only, the rate of reaction is also doubled and
(ii) on doubling the initial concentration of both A and B, there is a change by a factor of 8 in the rate of the reaction.
The rate of this reaction is given by
A
rate = k[A]2 [B]2
B
rate = k[A] [B]2
C
rate = k[A] [B]
D
rate = k[A]2 [B]
Explanation
R = k[A]m[B]n
... (i)
2R = k[2A]m[B]n
... (ii)
8R = k[2A]m[2B]n
... (iii)
from (i), (ii) and (iii), m = 1, n = 2
So, rate = k[A][B]2
4
AIPMT 2009
MCQ (Single Correct Answer)
In the reaction,
BrO$$_{3(aq)}^ - $$ + 5Br$$_{(aq)}^ - $$ + 6H+ $$ \to $$ 3Br2(l) + 3H2O(l).
The rate of appearance of bromine (Br2) is related to rate of disappearance of bromide ions as