JAMB - Chemistry (2007 - No. 1)
Trioxonitrate (V) acid is not used for preparing hydrogen gas from metals because it
is strongly oxidizing
is volatile
renders the metal passive
forms a layer of oxide on the metal
Wyjaśnienie
Nitric acid is not used in the preparation of hydrogen because it is a strong oxidizing agent, meaning it readily oxidizes the hydrogen gas produced during the reaction with a metal, converting it to water and thus preventing the collection of hydrogen gas; instead, acids like dilute hydrochloric acid or sulphuric acid are preferred for hydrogen production as they do not oxidize hydrogen.