Justify that the reaction : `2 Na(s) + H_(2) (g) rarr 2NaH (s)` is a redox change.

Explanation

Sincein the above reaction the compound formed is an ionic compound, which may also be represented as `Na^(+)H^(-)(S)` this suggests that one half reaction in this process is :
`2Na(s)to 2Na^(+)(g)+2e`
and the other half reaction is `H_(2)` (g)+2e `to 2H^(-)(g)`
This splitting of the reaction under examination into two half reactions autwmatically reveals that here sodium is oxidised and hydrogen is reduced, therefore, the complete reaction is redox change.