Question

Name with examples three common forms in which metals occur in nature? How do metals interact with dilute acids? [5 MARKS]

Answer 1

Each form of metal: 1 Mark
Each reaction: 1 Mark

1. Three common forms in which metals occur in nature are:

Sulphide form : Copper pyrite $\left({\text{CuFeS}}_2\right)$

Oxide form : Bauxite $\left({\text{Al}}_2{\text{O}}_3.2{\text{H}}_2\text{O}\right)$

Carbonate form : Calamine $\left({\text{ZnCO}}_3\right)$

2. Active metals (which lie above hydrogen in the activity series) generally interact with dilute HCl or dilute ${\text{H}}_2{\text{SO}}_4$ to give hydrogen gas. For example:

$\text{Zn (s)}+2\text{HCl (aq)}\to {\text{ZnCl}}_2\text{(aq)}+{\text{H}}_2\text{(g)}$

$\text{Mg (s)}+2\text{HCl (aq)}\to {\text{MgCl}}_2\text{(aq)}+{\text{H}}_2\text{(g)}$

The metals which lie below hydrogen in the activity series do not interact with dilute acids.