Oxidation numbers of oxygen in H2PO4 and H2O2 is respectively

-2 , -1

Explanation:

H2PO4=-1

+1 × 2 + +5 + 4 ×O=-1

7+ 4O =-1

4O= -8

O = -2

H2O2=0

+1 × 2 +2 x O =0

2 + 2O=0

O= -1

(As the oxidation number of Hydrogen is +1 , and we have 2 hydrogen atoms so we multiply by 2 , while the oxidation number of P is +5 in this equation, also the compound as a whole equals -1 , then we do the steps as followed)

(while the other compound as a whole equals zero , and doing steps as followed)

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the correct name for the n3 ion is azide. azide is a polyatomic anion with a -1 charge and is written as n3 -1. it consists of three nitrogen atoms bonded together. hope i . let me know if you need anything else.

i think   the answer is c hope i'm right