[Hemidol]

Draw two equivalent resonance forms for nitric acid, HNO3. How many sigma bonds are there? How
many pi bonds?


The structures I imagine will look like...

O=N-O-H
||
O

with a net overall charge of 0... not sure where the charges on atoms would be.


I'm really confused about sigma and pi bonds...

[UG]

You know how NO₃^- looks like? Add an H and you have yourself HNO₃

[blstrs]

Most simply, every single bond is a sigma bond.  Each additional shared pair between two atoms is a pi bond.

[Ranadeep]

The structure you imagined contains oxygen with 4 bonds which i think is not possible and also all Oxygens are attached to Nitrogen and no Peroxy bonds : )

NO₃^- is Resonance Hybridized [PM me for Structure : ) ] .. and it accepts a H⁺ and it may be added to any O^- randomly .. Then you get the stricture Like ..
              
             OH  
             /
     O<--N=O   1. nitrogen is SP² hybrdized,bonds in 120 with each other
                    2. SP²-P Sigma Coordinate Covalent Bond
                    3. SP₂-P , one Sigma and one Pi
                    4. SP₂-P , bond with O^- which again bonded to h+

Browse for CO₃^-2 for similarity so that you can be more clear .. it accepts to 2H⁺ and forums H₂CO₃

Hope it Helped and i am correct :  )

[Hemidol]

AH I see now. Thus this structure will have a total of 4 sigma bonds and 1 pi bond (as the double bond can indeed be considered sigma)--correct?

[Ranadeep]

Yeah 4 Sigma and 1 pi bond : ) .. yea a double bond = 1 Sigma + 1 Pi  . : )