Since
rate of consumption of HI is twice the rate of formation of H2 or I2, to
make them equal, the term D[HI]  is divided by 2 The rate of this reaction
is given by
Rate  of reaction  
[
]
[
]
[ ]
2
2
H
I
1
HI
2
t
t
t
∆
∆
∆
= −
=
=
∆
∆
∆
Similarly, for the reaction
5 Br- (aq) + BrO3
– (aq) + 6 H+ (aq)  ®  3 Br2 (aq) + 3 H2O (l)
Rate
Br
BrO
H
Br
H
= −
[
] = −

 = −
[
] =
[
] =
−
−
+
51
61
31
1
3
3
2
2
∆
∆
∆
∆
∆
∆
∆
∆
∆
t
t
t
t
OO
[
]
∆t
For a gaseous reaction at constant temperature, concentration is
directly proportional to the partial pressure of a species and hence, rate
can also be expressed as rate of change in partial pressure of the reactant
or the product Rationalised 2023-24
66
Chemistry
Intext Questions
Intext Questions
Intext Questions
Intext Questions
Intext Questions
3 1 For the reaction R ®  P, the concentration of a reactant changes from 0