Question

Resonance help!

Answer 1

Suppose we have to write resonating structures of formic acid. I did following and got 2 of them

Answer 2

But then I saw there are 2 more possible resonating structures. Can you explain how?

Answer 3

@Abhisar there's also a rule like certain resonance structures predominate more than others, although predominates is kind of a bad word: the resonance structures are representations of your molecule.

some things to consider: you want to minimize the number of charges in the resonance structure and ensure that positive charges are on the less electronegative elements while negative charges are on the more electronegative elements.

Answer 4

hey by any chance, is that a negative charge on the carbon there?



remember something though: the idea of electronegativity will help you:

take a look at what you've got going on in the structure too. take a look at what pi bonds exist and also take into consideration the electronegativity of the elements, in that molecule.

positive charges are less likely to be on more electronegative elements;

while negative charges are less likely to be on elements that are less electronegative

Answer 5

I would argue that this structure is a more reasonable depiction of the molecule, because those two oxygen atoms are going to be withdrawing electron density away from that carbon so that carbon is going to be more electropositive b/c of those two oxygens.