Observe the particles before and after the reaction. One molecule did not participate in the reaction. Remove the interfering particles to get the picture:

A. The components of tail gas are nitric oxide and carbon monoxide. According to the law of conservation of mass and the microscopic diagram of the product, it is known that the atomic number ratio in the product is 1: 2, so one substance in the product may be? Carbon dioxide;

B, according to the microscopic schematic diagram of reactants and products, there is a certain gap between molecules, so B is correct;

C, there are 1 molecules that make up the same compound before and after the reaction, indicating that the molecule did not participate in the reaction. Therefore, the number ratio of the two molecules participating in the reaction is1:1; Therefore, C is correct;

D. Molecules of products: one is a compound molecule composed of different kinds of atoms, and the other is a simple molecule composed of the same kind of atoms, so there are both simple materials and compounds in the reaction; So d is incorrect.

Therefore, the option is: d.