Based on first law of thermodynamics which of the following is correct

Identify the equation in which change in enthalpy is equal to change in internal energy

Two moles of an ideal gas is expanded isothermally and reversibly at 300 K from 1 L to 10 L . The enthalpy change in kJ is

$$\begin{aligned} & \text { If } \mathrm{C}(s)+\mathrm{O}_2(g) \rightarrow \mathrm{CO}_2(g), \Delta H=-X \\ & \mathrm{CO}(g)+\frac{1}{2} \mathrm{O}_2(g) \rightarrow \mathrm{CO}_2(g), \Delta H=-Y \end{aligned}$$ Calculate $\Delta_f H$ for $\mathrm{CO}_{(g)}$ formation