Question

The number of lone pairs present in phosphonic acid (phosphorus acid) is .........

Hint:

When counting lone pairs, consider the bonding environment of each atom and the valency of the central atom.

Answer 1

Correct Answer: 6

Step 1: Structure of phosphonic acid.
Phosphonic acid has the structure \( \text{H}_3\text{PO}_3 \), where phosphorus is bonded to three hydroxyl groups and has one lone pair of electrons.

Step 2: Analyzing lone pairs.
Phosphorus in this case has one lone pair, and the oxygen atoms in the hydroxyl groups have two lone pairs each. The total number of lone pairs in the molecule is the sum of the lone pairs on phosphorus and oxygen atoms.

Step 3: Conclusion.
The total number of lone pairs is \( \boxed{4} \) (one on phosphorus and three on oxygen).