KEAM 2014 Physics and Chemistry Paper

Let, the order of reaction wrt [NH4+],[NO2−] be xand y respectively.
Then, rate law, r=k[NH4+]×[NO2]γ
On substituting the values of different experiments,
(i) 0.020=k[0.010]x[0.020]γ
(ii) 0.020=k[0.015]x[0.020]γ
(iii) 0.005=k[0.010]x[0.010]γ
Dividing Eq. (i) by Eq. (ii) gives
(‌

0.020

0.030

)=(‌

0.010

0.015

)x
(‌

2

3

)1=(‌

2

3

)x or x=1
Dividing Eq. (i) by (iii) gives
‌

0.020

0.005

=(‌

0.020

0.010

)y
4=2y
(2)2=(2)y
or y=2
On substituting the values of x and y in the rate law, we get
r=k[NH4+][NO2−]2