In an acid-base neutralization reaction, the salt produced contains one metal atom (M), two nitrogen atoms and four oxygen atoms. Give the formulae of the acid and the base.

Explanation

The salt produced from the acid-base neutralization reaction is `M(NO_2)_2`
Thus, the valency of metal is 2 as valency of `NO_(2)^(-)` radical is 1.
The acid used for the formation of this salt is `HNO_2` and the base is `M(OH)_2`.
`M (OH)_2 + 2HNO_2 to M(NO_2)_2 + 2H_2O`