COMEDK 2023 Shift 1 Paper

To determine the overall order of the reaction given by the equation 2X+Y⟶A+B, we need to analyze how changes in the concentrations of reactants [X] and [Y] affect the initial rate of formation of A.
The rate law for this reaction can be represented as:
Rate =k[X]m[Y]n
Where:
k is the rate constant,
m is the order of the reaction with respect to X,
n is the order of the reaction with respect to Y,
the overall order of the reaction is m+n.
From the data provided:
Experiment 1: [X]=0.2,[Y]=0.2, Rate =12.0×10−3
Experiment 2: [X]=0.6,[Y]=0.4, Rate =14.4×10−2=144.0×10−3
Experiment 3: [X]=0.6,[Y]=0.8, Rate =5.76×10−1=576.0×10−3
Experiment 4: [X]=0.8,[Y]=0.2, Rate =48.0×10−3
To find m (the order with respect to X ):
Comparing Experiment 1 and Experiment 4 where [Y] is constant:
‌‌

‌ Rate ‌4

‌ Rate ‌1

=(‌

[X]4

[X]1

)m
‌‌

48.0×10−3

12.0×10−3

=(‌

0.8

0.2

)m
‌4=(4)m⟶m=1
To find n (the order with respect to Y ):
Comparing Experiment 2 and Experiment 3 where [X] is constant:
‌‌

‌ Rate ‌3

‌ Rate ‌2

=(‌

[Y]3

[Y]2

)n
‌‌

576.0×10−3

144.0×10−3

=(‌

0.8

0.4

)n
‌4=(2)n⟶n=2
The overall order of the reaction is m+n=1+2=3. Therefore, the correct option is: