The following two reactions are given together with their enthalpy changes. $2\text{C}(s) + 2\text{H}_2(g) \rightarrow \text{C}_2\text{H}_4(g) \quad \Delta H^\circ = +52.2\,\text{kJ mol}^{-1}$ $\text{C}_2\text{H}_2(g) + \text{H}_2(g) \rightarrow \text{C}_2\text{H}_4(g) \quad \Delta H^\circ = -175.8\,\text{kJ mol}^{-1}$ The information above may be used to determine the enthalpy change for the reaction below. $2\text{C}(s) + \text{H}_2(g) \rightarrow \text{C}_2\text{H}_2(g) \quad \Delta H^\circ = X$ What is the value of $X$?
- A$-228.0\,\text{kJ mol}^{-1}$
- B$-123.6\,\text{kJ mol}^{-1}$
- C$+123.6\,\text{kJ mol}^{-1}$
- D$+228.0\,\text{kJ mol}^{-1}$