10. THE S-BLOCK ELEMENTS (HM)
Explanation:
$\underset{\begin{smallmatrix}
\text{(Salt of strong} \\
\text{base }\!\!\,\And\,\!\!\text{ weak}
\\
\text{acid)}
\end{smallmatrix}}{\mathop{NaHC{{O}_{3}}}}\,\,\,\,\to \,\,\,N{{a}^{+}}\,+\underset{O{{H}^{-}}\,+\,C{{O}_{2}}}{\mathop{\underset{\downarrow }{\mathop{HCO_{3}^{-}}}\,}}\,$