Answer:
R=k[D]^2
Explanation:
Given that it is a decomposition reaction;
D--->product
Hence;
The rate law is;
R= k[D]^x ----(1)
When we triple the concentration of D we have;
[D]' = [3D]^x
Therefore;
R'= 3R
R'= k[D]'----(2)
Hence dividing (1) by (2);
R/R' = k[D]^x/k[D]'
R/9R = k[D]^x/k[3D]^x
1/9 = 1/3^x (take inverse of both sides)
9 = 3^x
3^2 = 3^x
x= 2
Hence the rate law;
R=k[D]^2
