Question

Using the conservation of baryon number, charge and lepton number, decide if the following reaction is possible:

a) p+n→p+n+p+p

Answer 1

The reaction

$$p+n→p+n+p+p$$

cannot occur because according to the conservation of charge number, the final charge (+3 from 3 protons) cannot be greater than initial charge (+1 from 1 proton).