Question

State one relevant observation for each of the following reactions:
Action of dilute hydrochloric acid on iron (II) sulphide

Answer 1

Reaction:
1. When Iron (II) sulphide or Ferric sulphide ($\text{FeS}$) is treated with dilute hydrochloric acid ($\text{HCl}$), it forms Ferric Chloride (${\text{FeCl}}_2$) with the release of the gas Hydrogen sulphide (${\text{H}}_2\text{S}$).
$\text{FeS (s)}+2\text{HCl (l)}\to {\text{FeCl}}_2\left(s\right)+{\text{H}}_2\text{S (g)}\uparrow$
Observation:
1. The odour of Hydrogen sulphide gas that is evolved has a rotten egg smell.