Two moles of magnesium bicarbonate on strong heating liberates….litres of carbon dioxide at STP

$$\begin{gathered} \mathrm{Mg}{\left({\mathrm{HCO}}_3\right)}_2\stackrel{∆}{\to }{\mathrm{MgCO}}_3\left(\mathrm{s}\right)+{\mathrm{H}}_2\mathrm{O}\left(\mathrm{g}\right)+{\mathrm{CO}}_2\left(\mathrm{g}\right); \\ {\mathrm{MgCO}}_3\left(\mathrm{s}\right)\stackrel{∆}{\to }\mathrm{MgO}\left(\mathrm{s}\right)+{\mathrm{CO}}_2\left(\mathrm{g}\right); \\ 44.8 \mathrm{litres} \mathrm{of} {\mathrm{CO}}_2 \mathrm{is} \mathrm{liberated} \mathrm{at} \mathrm{STP} \mathrm{by} 1 \mathrm{mole} \mathrm{of} \mathrm{Mg}{\left({\mathrm{HCO}}_3\right)}_2 \\ 89.6 \mathrm{litres} \mathrm{of} {\mathrm{CO}}_2 \mathrm{is} \mathrm{liberated} \mathrm{at} \mathrm{STP} \mathrm{by} 2 \mathrm{moles} \mathrm{of} \mathrm{Mg}{\left({\mathrm{HCO}}_3\right)}_2 \end{gathered}$$