In a flask of ‘V’ litres, 0.2 moles of O2, 0.4 moles of N2, 0.1 moles of NH3 and 0.3 moles of He gases are present at 27°C. If total pressure exerted by these non-reacting gases is 1 atm, the partial pressure exerted by N2 gas is
1) 0.4 atm 2) 0.3 atm 3) 0.2 atm 4) 0.1 atm
