What is the lewis structure for sodium bicarbonate?
The correct answer and explanation is:
Correct Answer:
The Lewis structure of sodium bicarbonate (NaHCO₃) consists of the following:
- Na⁺ (sodium ion): This ion does not form covalent bonds. It donates one electron and becomes a positive ion.
- HCO₃⁻ (bicarbonate ion): This is the main covalent structure, containing one hydrogen atom, one carbon atom, and three oxygen atoms. One of the oxygens is bonded to hydrogen (as –OH), one is double-bonded to carbon, and one carries a negative charge due to extra electrons.
The Lewis structure of the HCO₃⁻ ion is as follows:
O
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H–O–C–O⁻
Each atom is surrounded by dots representing valence electrons, showing how atoms share or donate electrons. The sodium ion (Na⁺) is drawn separately with no dots because it has given away its valence electron.
Explanation:
The Lewis structure shows how atoms in a compound are bonded and how electrons are distributed around them. Sodium bicarbonate, NaHCO₃, is made of one sodium ion and one bicarbonate ion. Sodium has one valence electron, which it loses easily to become Na⁺. Since it loses an electron, it does not form covalent bonds and appears separately in the structure as a cation.
The bicarbonate ion, HCO₃⁻, contains a central carbon atom bonded to three oxygen atoms. One of the oxygens forms a double bond with the carbon. Another oxygen is singly bonded to the carbon and also bonded to a hydrogen atom, making a hydroxyl group (–OH). The third oxygen is singly bonded to the carbon and carries a negative charge, accounting for the ion’s overall negative charge.
Carbon makes four bonds, and each oxygen has either two lone pairs or three if it carries a negative charge. Hydrogen forms one bond with oxygen. The negative charge on the ion is balanced by the positive charge of the sodium ion. This structure explains both the stability and solubility of sodium bicarbonate in water.