\(\begin{array}{l}
N{a_2}C{O_3} + Ca{(N{O_3})_2} \to CaC{O_3} + 2NaN{O_3}\\
C{O_3}^{2 - } + C{a^{2 + }} \to CaC{O_3}\\
FeS + 2HCl \to FeC{l_2} + {H_2}S\\
{S^{2 - }} + 2{H^ + } \to {H_2}S\\
NaHC{O_3} + HCl \to NaCl + C{O_2} + {H_2}O\\
HC{O_3}^ - + {H^ + } \to C{O_2} + {H_2}O
\end{array}\)