Question

Consider the reaction between chlorine trifluoride gas, CIF3(g), and ammonia gas, NH₃(g), represented by the equation
2CIF₃(g) + 2 NH₃(g) N₂ (g) + 6HF(g) + Cl₂ (g) ΔΗ° = - 1196 kJ
Calculate ΔΗ for ClF₂ (g)?