Question

Phosphorus has the oxidation state of + 3 in

• A. Phosphorous acid
• B. Orthophosphoric acid
• C. Hypophosphorous acid
• D. Metaphosphoric acid

Answer 1

The Correct Option is A

In this question, we need to determine which compound has phosphorus in the +3 oxidation state.

Let's analyze each option:

1. Phosphorous acid (H₃PO₃): In this compound, hydrogen has a typical oxidation state of +1 and oxygen -2. Solving for the oxidation state of phosphorus: 3(+1) + P + 3(-2) = 0 3 + P - 6 = 0 P = +3 So, phosphorus in phosphorous acid is in the +3 oxidation state.
2. Orthophosphoric acid (H₃PO₄): Similarly, using the same logic: 3(+1) + P + 4(-2) = 0 3 + P - 8 = 0 P = +5 Phosphorus in orthophosphoric acid is in the +5 oxidation state.
3. Hypophosphorous acid (H₃PO₂): Similarly, solving for phosphorus: 3(+1) + P + 2(-2) = 0 3 + P - 4 = 0 P = +1 Phosphorus in hypophosphorous acid is in the +1 oxidation state.
4. Metaphosphoric acid (HPO₃): Solving for phosphorus: 1(+1) + P + 3(-2) = 0 1 + P - 6 = 0 P = +5 Phosphorus in metaphosphoric acid is in the +5 oxidation state.

From the above analysis, only Phosphorous acid (H₃PO₃) has phosphorus in the oxidation state of +3.

Therefore, the correct answer is Phosphorous acid.