A diatomic gaseous species $A_{\mathit{2}}\mathit{\left(}g\right)$ decomposes into atomic A by first order kinetics as :

${\mathrm{A}}_2\left(\mathrm{g}\right)⟶2\mathrm{A}\left(\mathrm{g}\right)$

An empty flask was filled with A2 (g) and ${\mathrm{N}}_2$(g) at an initial pressure of 800 mm of Hg at 600 K and sealed. After a very long time, gases in the flask developed a pressure 1400 mm of Hg. If half-life for the decomposition process is 2 hr, what was the pressure in the flask after 4 Hr from start? Assume ${\mathrm{N}}_2$ to be an inert gas. [Find your answer in cm of Hg]