Question

Metals generally react with dilute acids to produce Hydrogen gas. Which one of the following metals does not react with dilute Hydrochloric acid?

• A. Magnesium
• B. Aluminum
• C. Iron
• D. Copper

Answer 1

The correct option is D

Copper

Explanation for correct option:

Option (D) Copper

• The metals can easily lose their electrons and form cations.
• The only metals that are able to replace the Hydrogen atom to form metal halide can produce Hydrogen gas with Hydrochloric acid.
• For that, the metals should be placed above the Hydrogen atom in the reactivity series of metals.
• Metals that are placed below the hydrogen atom in the reactivity series can't replace the Hydrogen atom.

• Since Copper is placed below the Hydrogen atom in the reactivity series of metals it can't replace the Hydrogen atom.
• Hence correct option

Explanation for incorrect options:

Option (A) Magnesium

• Since Magnesium is placed above the Hydrogen atom in the reactivity series of metals it can replace the Hydrogen atom to form Magnesium chloride.
  $\underset{\mathrm{Magnesium}}{\mathrm{Mg}\left(\mathrm{s}\right)}+\underset{\mathrm{Hydrochloric}\mathrm{acid}}{2\mathrm{HCl}\left(\mathrm{aq}\right)}\to \underset{\mathrm{Magnesium}\mathrm{chloride}}{\mathrm{MgC}{\mathrm{l}}_2\left(\mathrm{aq}\right)}+\underset{\mathrm{Hydrogen}}{{\mathrm{H}}_2\left(\mathrm{g}\right)}$
• Hence incorrect option

Option (B) Aluminium

• Since Aluminium is placed above the Hydrogen atom in the reactivity series of metals it can replace the Hydrogen atom to form Aluminium chloride.

$\underset{\mathrm{Aluminium}}{2\mathrm{Al}\left(\mathrm{s}\right)}+\underset{\mathrm{Hydrochloric}\mathrm{acid}}{6\mathrm{HCl}\left(\mathrm{aq}\right)}\to \underset{\mathrm{Aluminium}\mathrm{chloride}}{2\mathrm{AlC}{\mathrm{l}}_3\left(\mathrm{aq}\right)}+\underset{\mathrm{Hydrogen}}{3{\mathrm{H}}_2\left(\mathrm{g}\right)}$

• Hence incorrect option

Option (C) Iron

• Since Iron is placed above the Hydrogen atom in the reactivity series of metals it can replace the Hydrogen atom to form Iron chloride.

$\underset{\mathrm{Iron}}{\mathrm{Fe}\left(\mathrm{s}\right)}+\underset{\mathrm{Hydrochloric}\mathrm{acid}}{2\mathrm{HCl}\left(\mathrm{aq}\right)}\to \underset{\mathrm{Iron}\mathrm{chloride}}{\mathrm{FeC}{\mathrm{l}}_2\left(\mathrm{aq}\right)}+\underset{\mathrm{Hydrogen}}{{\mathrm{H}}_2\left(\mathrm{g}\right)}$

• Hence incorrect option

Hence the Option (D) Iron is the correct answer