In the following reaction the oxidation state of phosphorus changes from to ? P4 + H2O + HNO3 -> H3PO4 + NO

A) +4, +5
B) 0, +6
C) O, +5
D) +5, +6

C) 0, +5

Explanation:

P + H2O + HNO3 -> H3PO4 + NO

We consider all compounds that contain phosphorus in the equation

A substance that has no charge has a zero oxidation state

Hence at the reactant, phosphorus has an oxidation state of 0

Let us consider H3PO4 at the product side

Oxidation state of

H =+1×3=+3

O=-2×4=-8

P = ?

H3PO4 is a neutral compound and has 0 oxidation state

The sum of the individual oxidation states of each atoms in H3PO4 is equal to 0

Hence,

+3 + P + (-8) = 0

3+P-8=0

P=-3+8=+5

Hence the oxidation state of phosphorus in H3PO4 is +5

Therefore, the oxidation state of P in the reaction changed from

0 to +5

Phosphorus is said to have undergone oxidation