The amount of ${\mathrm{Na}}_2{\mathrm{CO}}_3$ required to react with HCl for obtaining 0.1 mole of ${\mathrm{CO}}_2$ is

${\mathrm{Na}}_2{\mathrm{CO}}_3+2\mathrm{HCl}\to 2\mathrm{NaCl}+{\mathrm{H}}_2\mathrm{O}+{\mathrm{CO}}_2$

1 mole ${\mathrm{Na}}_2{\mathrm{CO}}_3$= 1 mole ${\mathrm{CO}}_2$

106g of Sodium carbonate gives 44g of carbon dioxide gas that is 1 mole.

? –––– 0.1 mole

$\frac{0.1}{1}\times 106=10.6g.$