What is the Charge on Nitric acid (HNO3)? And Why?

The Charge of HNO3 (Nitric acid) is 0.

But the question is how can you say that the charge on HNO3 (Nitric acid) is 0?

Well you can say this by calculating its formal charge.

So let’s calculate the formal charge of HNO3 (Nitric acid).

If you are a visual learner like me, then here is a short two minute video for you.

Calculating the formal charge of HNO3 using lewis structure

In order to calculate the formal charge on HNO3 (Nitric acid), you should know the Lewis dot structure of HNO3 (Nitric acid).

Here is the lewis structure of HNO3.

Now using the above lewis structure of HNO3, you have to find the formal charge on each atom that is present in the HNO3 molecule.

For calculating the formal charge, you need to remember this formula;

Formal charge = Valence electrons – Nonbonding electrons – (Bonding electrons)/2

You can see the bonding and nonbonding electrons of HNO3 from the image given below.

So now let’s calculate the formal charge on each individual atom present in HNO3.

Formal charge on Hydrogen atom:
Valence electron = 1 (as it is in group 1 on periodic table) ^[1]
Nonbonding electrons = 0
Bonding electrons = 2

So according to the formula of formal charge, you will get;

Formal charge on Hydrogen = Valence electrons – Nonbonding electrons – (Bonding electrons)/2 = 1 – 0 – (2/2) = 0

So the formal charge on hydrogen atom is 0.

Formal charge on Nitrogen atom:
Valence electrons = 5 (as it is in group 15 on periodic table) ^[2]
Nonbonding electrons = 0
Bonding electrons = 8

So according to the formula of formal charge, you will get;

Formal charge on Nitrogen = Valence electrons – Nonbonding electrons – (Bonding electrons)/2 = 5 – 0 – (8/2) = 1+

So the formal charge on nitrogen atom is 1+

Formal charge on Oxygen atom (right side):
Valence electron = 6 (as it is in group 16 on periodic table) ^[3]
Nonbonding electrons = 6
Bonding electrons = 2

So according to the formula of formal charge, you will get;

Formal charge on Oxygen = Valence electrons – Nonbonding electrons – (Bonding electrons)/2 = 6 – 6 – (2/2) = 1-

So the formal charge on oxygen atom (which is on the right side) is 1-.

Formal charge on remaining Oxygen atoms:
Valence electron = 6 (as it is in group 16 on periodic table)
Nonbonding electrons = 4
Bonding electrons = 4

So according to the formula of formal charge, you will get;

Formal charge on Oxygen = Valence electrons – Nonbonding electrons – (Bonding electrons)/2 = 6 – 4 – (4/2) = 0

So the formal charge on oxygen atom is 0.

Now let’s put all these charges on the lewis dot structure of HNO3.

So there is overall 0 charge left on the entire molecule.

This indicates that the HNO3 (Nitric acid) has 0 charge.

I hope you have understood the above calculations of HNO3 (Nitric acid). 

Check out some other related topics for your practice.

Related topics:
Charge on Acetic acid (CH3COOH)
Charge of O3 (Ozone)
Charge of Neon (Ne)
Charge on IO3 (Iodate ion)
Charge of Argon (Ar)