Magnesium and manganese react with very dilute nitric acid to evolve hydrogen gas because they are more reactive metals that can displace hydrogen from nitric acid, even in its oxidizing environment.
Why do magnesium and manganese react with very dilute nitric acid to evolve hydrogen gas?
Share
Magnesium and manganese react with very dilute nitric acid to evolve hydrogen gas because nitric acid, in very dilute concentrations, acts as a less powerful oxidizing agent. In these conditions, the oxidation of hydrogen ions (H⁺) by nitric acid is less pronounced. As a result, hydrogen gas is allowed to evolve as the metal displaces hydrogen ions from the acid. The reduced oxidizing power of dilute nitric acid enables the typical acid-metal reaction, where the metal reacts with the acid to form metal nitrate and hydrogen gas. This behavior is in contrast to more concentrated nitric acid, where the oxidizing effects are dominant and hinder hydrogen gas evolution.