Two pure substances of equal molar masses are $\alpha$ and $\beta$ (where $\mathrm{\alpha }={\mathrm{AHCO}}_3$) and ($\beta ={\mathrm{AHCO}}_3$) and they decompose as shown :
 $\begin{array}{l}2\mathrm{\alpha }\stackrel{\mathrm{\Delta }}{⟶}{\mathrm{H}}_2\mathrm{O}+{\mathrm{CO}}_2+{\mathrm{A}}_2{\mathrm{CO}}_3 ...\left(\mathrm{i}\right)\\ \mathrm{\beta }\stackrel{\mathrm{\Delta }}{⟶}\mathrm{BO}+{\mathrm{CO}}_2 ...\left(\mathrm{ii}\right)\end{array}$
$6.2 \mathrm{g}$ of mixture of ${\mathrm{H}}_2\mathrm{O}$ and ${\mathrm{CO}}_2$ is obtained by $16.8 \mathrm{g}$ of $\alpha$. Find out the molar mass of $\alpha$ and $\beta$ and value of ${\left(\frac{\alpha +\beta }{2}\right)}^2$