Answer and explanation:
(c)
A represents the activation energy (the minimum amount of energy needed to start a reaction).
B represents the overall change in energy (the difference between the energy of the reactants and products).
(d)
The reaction profile diagram shows that the reaction is exothermic because the energy change is negative (the products have less energy than the reactants) which shows that energy is lost or given out to the surroundings.
(e)
HCl gas doesn't conduct electricity, but hydrochloric acid does because in HCl, there are hydrogen ions that are free to move so they can carry a charge.
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