JAMB - Chemistry (2001 - No. 17)
In which of the following reactions does reduction takes place
Fe2+ - e- → Fe3+
2O2- →O2 + 4e-
Cr – 2e- → Cr2+
2H+ + 2e- → H2
Spiegazione
Reduction is gain of electron and decrease in oxidation number. Option D is the only one with addition or gain of electron, as 2 electrons were gained by H ion to become Hydrogen molecule. There is also a decrease in oxidation from +2 to 0. Therefore option D is the correct answer