Answer:
Oxidation Number of Phosphorous = + 6
Step-by-step explanation:
According to Rules of Assigning Oxidation States;
i) The Oxidation State of Hydrogen atom in a compound is assigned as +1 except for Hydrides i.e. NaH and MgH₂ where it is assigned with -1.
ii) The Oxidation State of Oxygen in a compound is assigned as -2 except for Peroxides where it is given -1 and OF₂ where it is assigned with +1 respectively.
Oxidation State of P in H₂P₃O₁₀;
As over all molecule is neutral we can write it as,
H₂P₃O₁₀ = 0
Putting oxidation number of H and O,
(+1)₂ + P₃ + (-2)₁₀ = 0
(+2) + P₃ + (-20) = 0
+ 2 + (P)3 -20 = 0
(P)3 = + 20 - 2
(P)3 = + 18
P = + 18 ÷ 3
P = + 6