Chemistry · THERMODYNAMICS

Which of the following chemical reactions is endothermic yet known to proceed spontaneously under appropriate conditions?

1. \( \text{C}(\text{graphite}) + 2\text{S}(\text{l}) \rightarrow \text{CS}_2(\text{l}) \)
2. \( \frac{1}{2}\text{N}_2(\text{g}) + \frac{3}{2}\text{H}_2(\text{g}) \rightarrow \text{NH}_3(\text{g}) \)
3. \( \frac{1}{2}\text{H}_2(\text{g}) + \frac{1}{2}\text{Cl}_2(\text{g}) \rightarrow \text{HCl}(\text{g}) \)
4. \( \text{H}_2(\text{g}) + \frac{1}{2}\text{O}_2(\text{g}) \rightarrow \text{H}_2\text{O}(\text{l}) \)