What happens when Dilute Hydrochloric Acid is added to the Iron Filling

Answer: A single displacement reaction happens when the dilute hydrochloric acid (HCl) is added to the iron fillings. The iron displaces the hydrogen from the hydrochloric acid in this single displacement reaction. It results in the formation of iron chloride, whereas the remaining hydrogen is liberated as hydrogen gas. A single displacement is a chemical reaction where another replaces one element.

Fe(s)+  2HCl(aq) → FeCl₂(aq) + H₂(g)

For instance, 

Acid + Metal → Salt + Hydrogen gas 

Fe(s) + 2HCl(aq) → FeCl₂(aq) + H₂(g)

Fe – Iron

HCl – Hydrochloric acid

FeCl₂ – Iron (III) chloride

H₂(g)- Hydrogen gas

• Let us take the reaction that occurs between the acid and the metal
• While the addition of acid with metal results in the formation of salt and liberation of hydrogen gas
• This scenario will assume acid as the dilute Hydrochloric acid and iron as the metal
• When the dilute Hydrochloric acid is introduced to the iron filings and results in the formation of Iron(III) Chloride and liberation of Hydrogen gas

Thus, the hydrogen is displaced from the hydrochloric acid by the iron, resulting in the formation of Iron Chloride and liberation of Hydrogen gas via a single displacement reaction. 

A single displacement reaction is also referred to as a single replacement reaction. A single displacement reaction is a chemical reaction where one reacting element is replaced with other elements.