Formation of two moles of hydrogen chloride gas from the gases hydrogen and chlorine is a reaction for which $\Delta$H is -185 kJ.Which of the following statements is correct?
(i)The reaction is exothermic.
(ii)Enthalpy of the system decreases.
(iii)Heat is a "product".

Question

Quizplus · Accepted Answer

(i) The negative value of the enthalpy change (-185 kJ) indicates that the reaction is exothermic, as energy is released to the surroundings.
(ii) The enthalpy of the system decreases, as indicated by the negative value of the enthalpy change (-185 kJ). 
(iii) Heat is a "product" because it is released to the surroundings during the reaction.

Formation of Two Moles of Hydrogen Chloride Gas from the Gases