A closed vessel with rigid walls contains 1 mol of  92238U  and 1 mol of air at 298K. Considering complete decay of  92238U to 82206Pb,  the ratio of the final pressure to the initial pressure of the system at 298K is

Let us assume that          1 mol of air = X atm          During the reaction  92238U→82206Pb ,          8 ‘a’ particles released .          8 moles of ‘He’ particles released during the reaction.          \ 9 moles of gas released during reaction.          \Total pressure = 9 atm          = 9 times of original pressure