Question

Complete both resonance structures of nitrous acid, hno2by adding the missing lone pair electrons, multiple bonds, and non-zero formal charges. do not add curved arrows, reaction arrows, or plus signs between the structures.

Answer 1

The two resonating structures of Nitrous Acid are shown below. Lone pair of electrons, single and multiple bonds and non zero formal charges (red color) are also specified.

Among these two structures the structure on the left lacking formal charge is the most stable form. The instability of second resonating structure is due to the fact that it contains two formal charges (the lesser the number of formal charges the greater is the stability). Secondly in this structure one oxygen atom is having +1 formal charge. Oxygen being more electronegative feel hostile towards positive formal charge. 

Answer 2

In the resonance structure of nitrous acid lone pair of oxygen converted to the covalent bond and vice versa. Also, the formal charge on first oxygen is +1 and on second oxygen is -1. (Refer to the image attached).

Further explanation:

Resonance is a method to show the delocalized electrons in some molecules where a single Lewis structure cannot account for all the properties of the molecule. The different forms of a molecule that contribute to the structure are called resonance structures or canonical forms.  These structures may arise either by the interaction of two pi bonds or via the interaction between pi bonds and lone pairs. They differ only in the electron distribution.

The general rules followed to draw the resonance structures are as follows:

a. The $\pi$  electrons or a lone pair of electrons can change their positions, but the position of the atoms does not change.

b. The total number of valence electrons remains constant in all the resonance structure.

c. The transfer of electrons is shown by curved arrows.

d. No atom can have more than eight electrons in its valence shell except sulfur. Octet rule should be followed in all cases.

In Lewis dot structure of ${\text{HN}}{{\text{O}}_2}$ , the central nitrogen atom is single-bonded with one oxygen that contains two lone pair and bonded to hydrogen atom. Nitrogen is double-bonded with second oxygen atom.

In order to draw the resonance structure, lone pair of first oxygen is converted to the covalent bond between first oxygen and nitrogen which forms a double bond between first oxygen and nitrogen. Also, first oxygen gets +1 charge.

Simultaneously, one bond pair between second oxygen and nitrogen is converted into lone pair on oxygen, and also oxygen gets -1 charge.

The lone pair on the first oxygen is in resonance with the double bond between the nitrogen atom and the second oxygen atom. Therefore the first oxygen atom acquires +1 charge and second oxygen atom acquires-1 charge.

For the resonance structure (refer to the image attached).

Learn more:

1. Molecules and polyatomic ions cannot be adequately described using a single lewis structure.: brainly.com/question/6786947

2. Determine the lewis structure of butanal.: brainly.com/question/6215269

Answer details:

Grade: Senior school

Subject: Chemistry

Chapter: Resonance

Keywords: Resonance structure, nitrous acid, HNO2, formal charge, pi bond, lone pair, -1, +1 formal charge.