At a certain temperature, 0.200 moles of NO, 0.300 moles of Cl2, and 0.500 moles of ClNO were placed in a 25.0 L vessel and allowed to reach equilibrium:
2NO(g) + Cl2(g) = 2ClNO(g)
At equilibrium, 0.600 moles of ClNO were present. How many moles of Cl2 are present at equilibrium?