How is the enthalpy of reaction shown in this potential energy diagram?

as the difference of the energy of the reactants and the energy of the products

In the given potential energy diagram, the energy of product at higher level and energy of reactant at lower level. The for this reaction will be positive. So, the enthalpy of reaction is defined as the difference of the energy of the reactants and the energy of the products.

I hope this helps!

can you attach the