Hydrogen reacts with chlorine to form hydrogen chloride (hcl (g), mc012-1.jpghf = –92.3 kj/mol) according to the reaction below.
which statement is correct?
the enthalpy of the reaction is –184.6 kj, and the reaction is exothermic.
the enthalpy of the reaction is –184.6 kj, and the reaction is endothermic.
the enthalpy of the reaction is 184.6 kj, and the reaction is endothermic.
the enthalpy of the reaction is 184.6 kj, and the reaction is exothermic.

Given:

H2(g) + Cl2 (g) → 2HCl (g)

To determine:

The enthalpy of the reaction and whether it is endo or exothermic

Explanation:

Enthalpy of a reaction is given by the difference between the enthalpy of formation of reactants and products

ΔH = ∑nHf (products) - ∑nHf (reactants)

      = [2Hf(HCl)] - [Hf(H2) + Hf(Cl2)] = 2 (-92.3) kJ = - 184.6 kJ

Since the reaction enthalpy is negative, the reaction is exothermic

Ans: The enthalpy of reaction is -184. kJ and the reaction is exothermic