Equivalent weights of ${\mathrm{CO}}_2$ in the following reactions:

$2{\mathrm{NaHCO}}_3={\mathrm{Na}}_2{\mathrm{CO}}_3+{\mathrm{H}}_2\mathrm{O}+{\mathrm{CO}}_2$ and

${\mathrm{NaHCO}}_3+\mathrm{HCl}=\mathrm{NaCl}+{\mathrm{H}}_2\mathrm{O}+{\mathrm{CO}}_2$, are respectively:

A redox reaction among the following is:

(i) ${\mathrm{CdCl}}_2+2\mathrm{KOH}\to \mathrm{Cd}(\mathrm{OH}{)}_2+2\mathrm{KCl}$

(ii) ${\mathrm{BaCl}}_{2 }+{\mathrm{K}}_2{\mathrm{SO}}_4\to {\mathrm{BaSO}}_4+2\mathrm{KCI}$

(iii) ${\mathrm{CaCO}}_3\to \mathrm{CaO}+{\mathrm{CO}}_2$

(iv) $2\mathrm{Ca}+{\mathrm{O}}_2\to 2\mathrm{CaO}$

The equivalent volume of ${\mathrm{CO}}_2$ in the following reaction is:

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