Question

What happens when dilute HCl is added to iron fillings? Name the type of reaction involved.

Answer 1

When dilute HCl is added to iron fillings, iron chloride and hydrogen gas are formed.

$Fe\left(s\right)+2HCl\left(aq\right)\to FeC{l}_2\left(aq\right)+H_2\left(g\right)$

In this reaction iron displaces hydrogen from hydrochloric acid to form hydrogen gas. The displacement reaction takes place because iron is more reactive than hydrogen.