The solubility of gas A is $16 \mathrm{mg} / \mathrm{L}$ in water and its vapor pressure is $0.042 \mathrm{~atm}$. at $25^{\circ} \mathrm{C}$. In a closed system, the gas phase concentration of $\mathrm{A}$ is $10^{-3} \mathrm{~mol} / \mathrm{L}$. Assuming Ideal gas constant $(\mathrm{R})$ value as $0.0821 \mathrm{~L}-\mathrm{atm} / \mathrm{mol}-\mathrm{K}$, the concentration of gas $\mathrm{A}$ in water at $25^{\circ} \mathrm{C}$ is ___________ (in $\mathrm{mg} / \mathrm{L}$, $\text{rounded off to two decimal places).}$
