Question

Which of the following does not have any coordinate bond?

• A. $S{O}_2$
• B. $HN{O}_2$
• C. $H_{2}S{O}_3$
• D. $HN{O}_3$

Answer 1

The correct option is B $HN{O}_2$

$\left(a\right)$ Both sulphur and oxygen have $6$ valence electrons and they are short of $2$ electrons to complete their octet. Hence, sulphur and $1$ oxygen atom share two electrons each and form a double bond between them. Sulphur atom still has $4$ unshared electrons, that is two lone pairs to donate.
Hence, it donates its one lone pair to the other oxygen atom, forming a coordinate bond between them and by accepting this lone pair, octet of oxygen also gets completed and hence sulphur dioxide is formed.
$\left(b\right)$ Nitrogen has $5$ valence electrons and oxygen has six valence electrons. One oxygen forms single bonds each with H and N atoms, satisfying its octet. The other oxygen atom thus forms a double bond with N, which leads to completion of octet of all the atoms. Nitrogen has a lone pair of electron on it.
$\left(c\right)$ Both Sulphur and Oxygen have $6$ valence electrons and they are short of $2$ electrons to complete their octet. Sulphur forms a single bond each with $2$ oxygen atoms and these oxygen atoms form a single bond each with two hydrogen atoms, hence completing their octet but sulphur still has $2$ lone pairs. So, it donates its one lone pair to an oxygen atom, forming a coordinate bond.


$\left(d\right)$ $O$ forms single bonds with hydrogen and nitrogen. Other oxygen forms double bond with nitrogen, completing their octet. Nitrogen has 1 lone pair which it donates to oxygen which leads to completion of octet of both of them.