Answer : The formula of the missing product is, [tex]OH^_[/tex]
Explanation :
The given incomplete equation representing a reaction,
[tex]2Na(s)+2H_2O(l)\rightarrow 2Na^+(aq)+2__(aq)+H_2(g)[/tex]
When the sodium metal react with the water then it gives a colorless solution of sodium hydroxide and hydrogen gas. In the solution, sodium hydroxide is present in the form of ions i.e, [tex]Na^+[/tex] and [tex]OH^-[/tex] ions.
The balanced chemical reaction will be,
[tex]2Na(s)+2H_2O(l)\rightarrow 2Na^+(aq)+2OH^-(aq)+H_2(g)[/tex]
Therefore, the formula of the missing product is, [tex]OH^_[/tex]