Question 50 E
Question
Toothpastes containing sodium hydrogen carbonate (sodium bicarbonate) and hydrogen peroxide are widely used. Write Lewis structures for the hydrogen carbonate ion and hydrogen peroxide molecule, with resonance forms where appropriate.
Step-by-Step Solution
VerifiedThe Lewis structure for the following compounds is obtained as –
Hydrogen Carbonate Ion –
Hydrogen Peroxide -
Resonance shows the delocalization of electrons within a molecule or ion.
Lewis structure shows the electron dot arrangements within a molecule resulting in covalent bond.
With a formal negative charge on two oxygen atoms, the carbonate dianion can be represented as \({\rm{(O = )C( - }}{{\rm{O}}^{\rm{ - }}}{{\rm{)}}_{\rm{2}}}\). Carbonate forms bicarbonate when a hydrogen ion is added, and the Lewis structure \({\rm{(O = )C( - }}{{\rm{O}}^{\rm{ - }}}{\rm{)(OH)}}\) is formed. The bonding involves \(24\) valence electrons: four from carbon, eight from oxygen, and one each from the negative charge and hydrogen.
Below is the Lewis structure of \({\rm{HCO}}_{\rm{3}}^{\rm{ - }}\) –
Below are the resonance forms of \({\rm{HCO}}_{\rm{3}}^{\rm{ - }}\) –
Therefore, the Lewis Structure and resonance forms for \({\rm{HCO}}_{\rm{3}}^{\rm{ - }}\) are obtained.
Hydrogen peroxide (\({{\rm{H}}_{\rm{2}}}{{\rm{O}}_{\rm{2}}}\)) has two \({\rm{O - H}}\) bonds and one \({\rm{O - O}}\) bond in its Lewis structure. In addition, each oxygen atom has two lone pairs. The Lewis structure of \({{\rm{H}}_{\rm{2}}}{{\rm{O}}_{\rm{2}}}\) is shown using the concept of total valence electrons of oxygen and hydrogen atoms.
Below is the Lewis structure of \({{\rm{H}}_{\rm{2}}}{{\rm{O}}_{\rm{2}}}\) –
As, there are no multiple bonds in \({{\rm{H}}_{\rm{2}}}{{\rm{O}}_{\rm{2}}}\), so it cannot have resonance.
Therefore, the Lewis Structure for \({{\rm{H}}_{\rm{2}}}{{\rm{O}}_{\rm{2}}}\) is obtained.