Relative Reactivities of Metals
Which metals can displace H2 from acid?
The standard hydrogen half-reaction represents the reduction of
H+ from acids to form molecular hydrogen, H2:
The metals Li through Pb lie below hydrogen in the electromotive series
Table 21.2 (P 911). These will give a positive Eocell when reducing H+.
For example iron:
Fe(s) Fe2+(aq) + 2 e- -Eo = 0.44 V [oxidation]
2 H+(aq) + 2 e- H2 (g) Eo = 0.00 V [reduction]
Fe(s) + 2 H+(aq) H2 (g) + Fe2+(aq) Eocell = 0.44 V
If Eocell of metal A for the reduction of H+ is more positive than Eocell
of metal B, metal A is a stronger reducing agent than metal B. A is
more reactive than B and is a more ìactiveî metal.
| Previous slide | Next slide | Back to first slide | View graphic version |