$ \ \text {CaCO}_3+2\ \text {HCl}\xlongequal[\ \ \ \ \ \ ]{\ \ \ \ \ \ }$
$ \ \text {CaCl}_2+\ \text {H}_2\ \text {O}+\ \text {CO}_2↑$
$ \ \text {Na}_2\ \text {CO}_3+2\ \text {HCl}\xlongequal[]{}$
$ 2\ \text {NaCl}+\ \text {H}_2\ \text {O}+\ \text {CO}_2↑$