Question

Metals generally react with the dilute acid to produce hydrogen gas. Which one of the following metals does not react with dilute hydrochloric acid?
(A) Magnesium
(B) Aluminium
(C) Iron
(D) copper

Answer 1

Hint: We can find which of the following metals do not react with the hydrochloric acid, if we know about the reactivity series of the metal. Reactivity series is a table which will arrange the metals in the decreasing order, according to their reactivities.

Complete Solution :
Let us first understand what a metal is. Metals will easily lose their electrons and will form the cations. Metals can produce hydrogen gas with hydrochloric acid only when the metal will be able to replace the hydrogen atom from the HCl. In order to replace the hydrogen atom from the HCl gas, the metals should be placed above the hydrogen atom in the reactivity series of metals. Metals which cannot replace hydrogen will be placed below the hydrogen atom in the reactivity series. Less reactive metals such as Silver, copper and Gold will be placed below the hydrogen atom in the reactivity series and therefore they do not produce hydrogen gas. Certain metals like Aluminium, magnesium and Zinc are highly reactive and they produce hydrogen gas with hydrochloric acid.
Let us see one example.
\[Mg + 2HCl \to MgC{l_2} + {H_2}\]
Hence copper is the metal which does not produce the hydrogen gas.
So, the correct answer is “Option D”.

Note: Let us remember certain characteristics of the metals, they are:
- The metals are said to be the good conductor of heat and electricity.
- Metals are highly malleable and ductile.
- Metals will be having a shiny appearance.
- Metals will make a ringing sound, therefore it is sonorous.