Define Oxidation number. Find the Oxidation number of a. Carbon in CO2. b. Sulfur in H2SO4. c. Phosphorus in PO4 3 - d. Manganese in MnO4 2-

An oxidation number is a number that is assigned to an atom in a substance. The oxidation number could be positive, negative, or zero depending on if the electrons are lost or gained.

Generally Oxygen has - 2 oxidation number because it gains 2 electrons.

and a hydrogen atom has + 1 oxd. no.

Based on the above info, we can calculate for others.

a) CO2

x + 2 (-2) = 0 [We equate with 0 because net charge is 0)

so, x = + 4

Carbon ox. no. is = + 4

b) H2SO4

2 (+1) + x + 4 (-2) = 0

2 + x - 8 = 0

so, x = 6 (sulphur)

c) (PO4) 3-

x + 4 (-2) = - 3

x = + 5 (Phophorus)

d) (MnO4) 2-

x + 4 (-2) = - 2

x = + 6 (Manganese)