Why naoh does not react with solid sodium carbonate??

Q. The gases produced when $18$ g carbon reacts with $5$ L of oxygen at $18$ and $5$ atm pressure are treated with $0.5$ L of $2MNaOH$. The concentration of sodium carbonate produced by the reaction of $C{O}_2$ with $NaOH$ is_________. (as nearest integer)

Q. Why does sodium react vigorously with water?

Q. Which does not react with $I_2$ & NaOH?