The curves represent two possible reaction paths for the decomposition of ammonia, NH3- one can conclude correctly from the graph that the heat of the reaction corresponds to which labeled interval (A,B,C,D,E)
The reaction Heat or ΔH corresponds to the interval A
Reaction Heat is defined as the net change in enthalpy in a chemical reaction. To measure Reaction Heat, the intermediate path doesn't matter, but only the initial and final states. So, the interval that measures the difference between the initial and final states in this reaction is the interval A, and calculating the enthalpy difference between those two points will give the ΔH of reaction. Have a nice day!
