The reaction $2N_2O_5 (g) \to 4NO_2 (g) +O_2 (g)$ follows first order kinetics. The pressure of a vessel containing only $N_2O_5$ was found to increase from $50\; mm \;Hg$ to $87.5\; mm \;Hg$ in $30\; min$. The pressure exerted by the gases after $60 \;min$. will be (Assume temperature remains constant) :

Question

( A ) 125 mm Hg
( B ) 116.25 mm Hg
( C ) 150 mm Hg
( D ) 106.25 mm Hg