Question

energy diagram
energy
reaction progress
what does line c represent?
transition state
energy of the products
activation energy (forward)
enthalpy of reaction

Explanation:

In a reaction energy diagram, the enthalpy of reaction (ΔH) is the difference in energy between the products and the reactants. The line C here shows the energy difference between the products and reactants (since the reactants are at a lower energy level and products at a higher, or vice versa depending on the diagram, but in this case, the vertical line C represents the enthalpy change). The transition state is the peak, activation energy (forward) is the energy from reactants to transition state, and energy of products is the final energy level. So line C represents the enthalpy of reaction.

Answer:

enthalpy of reaction