Question

Magnesium displaces hydrogen from dilute acid solution because ______.

Options

• The oxidation potential of magnesium is less than that of hydrogen.

• The reduction potential of magnesium is less than that of hydrogen.

• Both magnesium and hydrogen have same oxidation potential.

• Both magnesium and hydrogen have same reduction potential.

Answer 1

Magnesium displaces hydrogen from dilute acid solution because the reduction potential of magnesium is less than that of hydrogen.

Explanation:

The standard reduction potential of magnesium is \[\ce{E^{\circ}_{Mg^{2+}/Mg}}\] = −2.37 V, which is much lower than that of hydrogen (0.00 V). A lower (more negative) reduction potential means magnesium is more easily oxidised than hydrogen. Therefore, magnesium displaces hydrogen from dilute acid by donating electrons to H⁺ ions.

\[\ce{Mg_{(s)} + 2H^+_{ (aq)} -> Mg^{2+}_{ (aq)} + H2_{(g)}}\]