Given the data in the table below and ΔH°_rxn for the reaction SO₂Cl₂ (g) + 2 H₂O (l) → H₂SO₄ (l) + 2HCl (g) ΔH° = -62 kJ
ΔH°_f of HCl (g) is __________ kJ/mol.

Question

Given the data in the table below and ΔH°_rxn for the reaction SO₂Cl₂ (g)+ 2 H₂O (l)→ H₂SO₄ (l)+ 2HCl (g)ΔH° = -62 kJ ΔH°_f of HCl (g)is __________ kJ/mol.

Quizplus · Accepted Answer

From the given reaction, we can see that 2 moles of HCl (g) are produced per mole of reaction. Thus, the enthalpy change for the formation of one mole of HCl (g) is half of the enthalpy change for the reaction.

ΔH°rxn = -62 kJ/mol
ΔH°f (2HCl (g)) = (-62 kJ/mol) / 2 = -31 kJ/mol

However, the question asks for ΔH°f of HCl (g), not 2HCl (g). Therefore, we need to divide the enthalpy change by the stoichiometric coefficient of HCl (g), which is 1.

ΔH°f (HCl (g)) = (-31 kJ/mol) / 1 = -31 kJ/mol

The enthalpy change for the formation of HCl (g) is -31 kJ/mol. We can see that the correct answer is (C).

Given the Data in the Table Below and ΔH°rxn for the Reaction

Given the Data in the Table Below and ΔH°_rxn for the Reaction