Question

Would the N=O bond in HNO2 be longer, shorter, or the same length as the N-O bonds in NO2-?

Answer 1

${\text{N}}={\text{O}}$ bond in ${\text{HN}}{{\text{O}}_2}$ is $\boxed{{\text{shorter}}}$ than ${\text{N}}-{\text{O}}$ bond in ${\text{NO}}_2^-$.

Further explanation:

Bond length:

The average distance between the nuclei of the bonded atoms in a molecule. When two similar atoms are bonded together, half of the bond length is known as the covalent radius. The unit of bond length is picometer.

The order of bond length of various bonds is as follows:

${\text{Triple bond }}$

Bond order:

It is used to evaluate the number of electrons that are included in the bond formation between two atoms in a molecule. It determines the stability of the chemical bond. The value of bond orders for single, double and triple bonds are 1, 2 and 3 respectively.

Higher the bond order, smaller will be the bond length and vice-versa. Bond order between the atoms is inversely proportional to the bond length between the atoms.

The resonating structures of ${\text{HN}}{{\text{O}}_2}$ are drawn in the attached image. Structure (II) is highly unstable so ${\text{HN}}{{\text{O}}_2}$exists primarily in the form of structure (I). So ${\text{N}}={\text{O}}$bond in ${\text{HN}}{{\text{O}}_2}$is a double bond, and its bond order is 2.

The resonating structures of ${\text{NO}}_2^-$ are drawn in the attached image. Both structures (I) and (II) are equally stable. So ${\text{N}}-{\text{O}}$bond acquires partial double bond character and therefore its bond length is shorter than its actual bond length.

Bond order in ${\text{HN}}{{\text{O}}_2}$ is higher than that in ${\text{NO}}_2^-$. Therefore ${\text{N}}={\text{O}}$ bond in ${\text{HN}}{{\text{O}}_2}$ is shorter than ${\text{N}}-{\text{O}}$ bond in ${\text{NO}}_2^-$.

Learn more:

1. Molecular shape around the central atoms in the amino acid glycine: brainly.com/question/4341225

2. What causes water molecules to have a bent shape? brainly.com/question/1979769

Answer details:

Grade: Senior School

Subject: Chemistry

Chapter: Covalent bonding and molecular structure

Keywords: NO2-, HNO2, bond order, bond length, bond order, smaller, triple bond, single bond, double bond.

Answer 2

Explanation:

Bond order is inversely proportional to the bond length.

$B.O\propto \frac{1}{B.L}$

In $HNO_2$ molecule. one nitrogen is double bonded to nitrogen and one oxygen is single bonded to nitrogen and hydrogen bond.

• Bond order between the (N=O) bond is 2 which means that bond length between the (N=O) bond is shorter than that of the N-O bond.
• Bond order between the (N-O) bond is 1 which means that bond length of the N-O bond is longer than that of the bond length of (N=O) bond.