Incorrect statement about pyrophosphorous acid H4P2O5 is:

(A) It contains P in +5 oxidation state.

(B) It is dibasic.

(C) It is strongly reduced in nature.

(D) It contains one P-O-P bond.

To determine which statement about pyrophosphorous acid (H4P2O5) is incorrect, let's analyze each option carefully. Pyrophosphorous acid is an interesting compound with unique properties, and understanding its structure and characteristics will help clarify the correct answer.

Analyzing the Statements

Statement A: It contains P in +5 oxidation state.

This statement is incorrect. In pyrophosphorous acid, phosphorus is present in different oxidation states. Specifically, one phosphorus atom is in the +5 oxidation state, while the other is in the +3 oxidation state. Therefore, this statement does not accurately describe the oxidation states of phosphorus in the compound.

Statement B: It is dibasic.

This statement is correct. Pyrophosphorous acid can donate two protons (H+) in a reaction, which qualifies it as dibasic. This property is due to the presence of two acidic hydrogen atoms in its structure, allowing it to participate in acid-base reactions effectively.

Statement C: It is strongly reduced in nature.

This statement is generally considered true. Pyrophosphorous acid can act as a reducing agent, particularly in certain chemical reactions. Its ability to donate electrons makes it a candidate for reduction processes, although the term "strongly" can be subjective depending on the context of the reaction.

Statement D: It contains one P-O-P bond.

This statement is accurate. Pyrophosphorous acid has a structure that includes a P-O-P bond, which is characteristic of pyrophosphate compounds. This bond is formed between two phosphorus atoms, linking them through an oxygen atom.

Conclusion

After evaluating each statement, the incorrect statement about pyrophosphorous acid is (A) "It contains P in +5 oxidation state." This misrepresents the oxidation states of phosphorus in the compound. Understanding these nuances is crucial for grasping the chemistry of pyrophosphorous acid and its behavior in various chemical contexts.