One mole of N2O4(g) at 300 K temperature is kept in a closed vessel at 1 atm pressure. It is heated to a temperature of 600 K when 20% of N2O4(g), by mass decomposes to give NO2(g). The resultant pressure will be
1
1.2 atm
2
2.4 atm
3
2.0 atm
4
1.0 atm