Oxidation state of phosphorus in its oxoacids

This type of question, asked 3 times: 2021 Paper 5, 2021 Paper 16, 31 Jan 2023. All 3 questions below, oldest first.

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Question 1
2021 Paper 5
47 $Match List-I with List-II. List-I (Name of oxoacid) List-II (Oxidation state of P) (A) Hypophosphorous acid (i) +5 (B) Orthophosphoric acid (ii) +4 (C) Hypophosphoric acid (iii) +3 (D) Orthophosphorous acid (iv) +2 (v) +1 Choose the correct answer from the options given below:$
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Question 2
2021 Paper 16
23 $H_{4}P_{2}O_{7};H_{4}P_{2}O_{6}$
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Question 3
31 Jan 2023
51 $The oxidation state of phosphorus in hypophosphoric acid is +$

Question 1