Aqua regia, a mixture of HCl and HNO₃, has been used since alchemical times to dissolve many metals, including gold. Its orange color is due to the presence of nitrosyl chloride. Consider this one-step reaction for the formation of this compound:NO(g) + Cl₂(g) → NOCl (g) + Cl(g) ΔH° = 83KJ(b) Calculate Ea(rev) .