‘x’ moles of N2O4 is taken at P1 atm in a closed vessel & heated. When 75% of N2O4 dissociated at equilibrium, total pressure at equilibrium was found to be P2 atm. The relation between P1 and P2 is

Initial moles of N2O4 = xInitial pressure of N2O4 = P1Degree of decomposition of N2O4moles of N2O4 decomposed = 0.75xmoles of N2O4 at equilibrium = (x - 0.75 x) =0.25xEquiolibrium pressure = P21 mole of N2O4 gives 2 moles of NO20.75 moles  of N2O4 gives _____ of NO2moles of NO2 formed at equilibrium = 1.5xTotal moles at equilibrium = x - 0.75x + 1.5x =1.75xPressure of gas α number of moles