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

Explanation

Since in 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 :
`2 Na(s) to 2 Na^(+) (g) + 2 e^(-)` and the other half reaction is :
`H_(2)g + 2 e^(-) to 2 H^(-) (g)`
This splitting of the reaction under examination into two half reactions automatically reveals that here sodium is oxidised and hydrogen is reduced , therefore , the complete reaction is a redox change .