Q.5 The number of phosphorous-hydrogen bonds in H 3 PO2 is ____
H3PO2, known as hypophosphorous acid, contains exactly 2 phosphorus-hydrogen (P-H) bonds. This structure explains its strong reducing properties due to the presence of these direct P-H linkages.
Molecular Structure of H3PO2
Hypophosphorous acid (H3PO2) features phosphorus at the center, bonded to one double-bonded oxygen (P=O), one hydroxyl group (P-OH), and two hydrogen atoms directly attached to phosphorus (two P-H bonds). Phosphorus expands its octet using d-orbitals, achieving four bonds total.
The formula reflects this: two H atoms link directly to P, while the third H attaches via oxygen. This arrangement confirms 2 P-H bonds.
Correct Answer Explanation
The number of phosphorus-hydrogen bonds in H3PO2 is 2. Sources consistently describe the structure as (HO)PH2=O, with two direct P-H bonds responsible for its dibasic nature and reducing behavior.
These P-H bonds are non-ionizable and contribute electrons easily, unlike P-OH bonds.
Common Options Analysis
In multiple-choice questions, options often include 0, 1, 2, or 3 for P-H bonds in H3PO2. Here’s a breakdown:
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Reducing Properties Insight
H3PO2 acts as a stronger reducing agent than H3PO3 because it has two P-H bonds versus one. These bonds release H+ and electrons readily due to low P-H bond polarity.
This property finds use in electroplating and organic reductions.
