Let the rate equation is Rate =k[A]]x[B]y Therefore, we can write 2×10−3=k[0.1]x[0.1]y ...........(i) 4×10−3=k[0.2]x[0.1]y ...........(ii) 1.6×10−2=k[0.2]x[0.2]y ...........(iii) (ii) ÷ (i);
4×10−3
2×10−3
=
k[0.2]x[0.1]y
k[0.1]x[0.1]y
⇒
2
1
=
(0.2)x
(0.1)x
=(
2
1
)x ∴x=1 (ii) ÷ (iii);
4×10−3
1.6×10−2
=
k[0.2]x[0.1]y
k[0.2]x[0.2]y
⇒
1
4
=
(0.1)y
(0.2)y
=(
1
2
)y ∴y=2 ∴ Rate =k[A]1[B]2 First order with respect to A while second order with respect to B.