Chapter 20, Problem 20.1VP

Interpretation Introduction

Interpretation: The Lewis structure of ${\text{HPO}}_{\text{3}}{}^{2-}$ ion is to be drawn.

Concept introduction: The Lewis structures are diagrams that give information about the bonding electron pairs and the lone pairs of electrons in a molecule. They are similar to electron dot structure.

To determine: The Lewis structure of ${\text{HPO}}_{\text{3}}{}^{2-}$ ion.

Answer to Problem 20.1VP

The Lewis structure of ${\text{HPO}}_{\text{3}}{}^{2-}$ ion is shown in Figure 2.

Explanation of Solution

The photochemical reaction of sodium hydrogen phosphate with formaldehyde is,

Figure 1

It may have played a role in the formation of nucleic acids before life existed on Earth.

The given ion is hydrogen phosphite which has a molecular formula ${\text{HPO}}_{\text{3}}{}^{2-}$ It consists of hydrogen, phosphorus and oxygen atoms which belong to groups $1,$ $7$ and $16$ respectively. Therefore, hydrogen has one, sulfur has five and oxygen has six valence electrons. The total valence electrons in ${\text{HPO}}_{\text{3}}{}^{2-}$ are calculated as,

$\begin{array}{c}\text{1H}+1\text{P}+3\text{O}+2=1\left(1\right)+1\left(5\right)+3\left(6\right)+2\\ =1+5+18+2\\ =26\end{array}$

The skeleton structure is drawn in which phosphorus act as a central metal atom. It forms $1$ double bond with one of the oxygen atom. It forms single bond with two oxygen atoms and hydrogen atom to complete the octet. The Lewis structure of ${\text{HPO}}_{\text{3}}{}^{2-}$ is shown in Figure 2.

Figure 2

Conclusion

The Lewis structure of ${\text{HPO}}_{\text{3}}{}^{2-}$ ion is shown in Figure 2.