Question

The oxoacid of phosphorus in which phosphorus has the lowest oxidation state is ______.

Options

• hypophosphorus acid

• orthophosphoric acid

• pyrophosphoric acid

• metaphosphoric acid

Answer 1

The oxoacid of phosphorus in which phosphorus has the lowest oxidation state is hypophosphorus acid.

Explanation:

Hypophosphorus acid (H₃PO₂) is the oxoacid of phosphorus in which phosphorus has the lowest oxidation state of +1. This acid contains one \[\ce{P - OH}\] group and two \[\ce{P - H}\] bonds, which indicates the lower oxidation state of phosphorus compared to other phosphorus oxoacids where phosphorus is in higher oxidation states, such as +3 or +5. Therefore, hypophosphorous acid represents the oxoacid with the lowest oxidation state of phosphorus among the options given.