Question

What happens when dilute hydrochloric acid is added to iron filings?
(A) Hydrogen gas and iron chloride are produced
(B) Chlorine gas and iron hydroxide are produced
(C) No reaction takes place
(D) Iron salt and water are produced

Answer 1

Hint: When dilute hydrochloric acid is added to iron feelings the single displacement reaction takes place. Due to a single displacement reaction the iron displaces hydrogen from hydrochloric acid and achieves the final product.

Complete Step by step solution:
Let us consider the reaction between acid and metal
Addition of acid with metal gives salt and hydrogen gas.
In this case, acid is dilute hydrochloric acid and metal is iron.
When dilute Hydrochloric acid is added to iron filings, iron(II) chloride & hydrogen gas is produced. In this reaction iron displaces hydrogen from hydrochloric acid to form iron chloride & hydrogen gas this reaction is a single displacement reaction.
The chemical reaction is given below:
$Fe_{(s)}+2HCl_{(dil)} \longrightarrow {FeCl_{2}{(aq)}}+{H_{2}{(g)} \uparrow}$

Additional Information:
> Single Displacement Reaction is a chemical reaction in which one element replaces another element in a compound. Sometimes a single displacement reaction is also called a single replacement reaction.
> Let's consider another example of a single displacement reaction when potassium reacts with water, a colorless solid compound named potassium hydroxide formed and hydrogen gas are released.
> When an acid reacts with metals hydrogen gas is evolved in the form of bubbles and reaction is an exothermic reaction.

Note: When iron reacts with chlorine it forms iron(iii) chloride by redox reaction while when iron reacts with hydrochloric acid it forms iron(ii) chloride.