When N2O5 is heated at temp. T, it dissociates as N2O5 (g) ⇌ N2O3 (g) + O2 (g), Kc =2.5. At the same time N2O3 also decomposes as N2O3 (g) ⇌ N2O(g) + O2 (g). If initially 4.0 moles of N2O5 are taken in 2.0 litre flask and allowed to attain equilibrium, concentration of O2 was formed to be 2.5M. Equilibrium concentration of N2O is –
(a) 2.0
(b) 1.0
(c) 0.334
(d) None of these