JAMB - Chemistry (1985 - No. 45)
Hydrogen is not liberated when trioxonitrate(v)acid reacts with zinc because
zinx is not rendered passive by acid
hydrogen produced is oxidized to water
oxides of nitrogen are produced
all nitrates are soluble in water
trioxonitrate(v)acid is a strong acid
Spiegazione
When metals react with nitric acid, hydrogen gas is liberated. Nitric acid is a very strong oxidizing agent. So , it oxidizes the hydrogen gas formed during the reaction to form water and an oxide of nitrogen.
\(Zn+4HNO_{3} \to Zn(NO_{3})_{2} + 2NO_{2} + 2H_{2}O\)