Write the ions present in a solution of Na2CO3. Express your answers as chemical formulas separated by a comma. Offset subscripts and charges on each ion.
The Correct Answer and Explanation is:
Correct Answer:
Na⁺, CO₃²⁻
Explanation:
When sodium carbonate (Na₂CO₃) is dissolved in water, it dissociates completely into its constituent ions because it is an ionic compound and highly soluble. Sodium carbonate is made of two sodium ions (Na⁺) and one carbonate ion (CO₃²⁻).
Dissociation Process:
The chemical formula of sodium carbonate indicates that it contains two sodium atoms and one carbonate group. Upon dissolving in water, the dissociation can be represented by the following balanced chemical equation:
Na₂CO₃ (s) → 2Na⁺ (aq) + CO₃²⁻ (aq)
Here is what happens step by step:
- Sodium ions (Na⁺) are monovalent cations, meaning each carries a +1 charge. In sodium carbonate, there are two of these to balance the charge of the anion.
- Carbonate ion (CO₃²⁻) is a polyatomic anion with a -2 charge. It consists of one carbon atom covalently bonded to three oxygen atoms, and the whole ion carries a 2− charge.
The charges must balance to make the original compound neutral. That is why two Na⁺ ions (each +1) balance the single CO₃²⁻ ion (−2).
Nature of the Ions in Solution:
In solution:
- Na⁺ ions remain freely hydrated in water. They do not hydrolyze and are considered neutral in acid–base terms.
- CO₃²⁻ ions can react with water in a process known as hydrolysis, where they accept hydrogen ions (protons) from water to form HCO₃⁻ (bicarbonate ion) and OH⁻ (hydroxide ion). This gives sodium carbonate a basic character in solution.
In summary, the ions present in a sodium carbonate solution are Na⁺ and CO₃²⁻, reflecting complete dissociation in aqueous media.
