Exercise 1 | Oxidation-Reduction Reactions

Determine the oxidation number of the elements in each of the following compounds:

SF4, N2, Na2SO4 and MnO4-?

SF4 ⇒ 4 F- + S⇒ SF4 is neutral: 0 = 4(-1) + x

oxidation states: S = +4 and F = -1

 

N2 ⇒ 2 N ⇒ oxidation state: N = 0

 

Na2SO4 ⇒ 2 Na+ + 4 O2- + Sx ⇒ Na2SO4 is neutral: 0 = 2(+1) + x + 4(-2)

oxidation states: Na = +1; S = +6 and O = -2

 

MnO4- ⇒ 4 O2- + Mnx ⇒ MnO4- is negatively charged: -1 = x + 4(-2)

oxidation states: Mn = +7  and O = -2