Question $2$: "please solve it in paper"

A tank of chlorine contains $1000kg$ of chlorine at $50-$bar gauge $(1$ bar $=100,000Pa).$ What is the maximum hole diameter $($in $mm)$ in this tank that will result in a continues downwind concentration equal to the ERPG$-1$ at a downwind distance of $300m?$ Assume $1$ atm, $25C,$ a molecular weight of chlorine of $70\mathrm{.}9,$ and that all the liquid chlorine vaporizes. Assume rural conditions, the stability class is $F$ and the wind speed is $2\frac{m}{s}.$