When dry solid sodium carbonate (Na2CO3) is dissolved in water, it undergoes a reaction known as hydration or dissolution. The reaction can be represented by the following chemical equation:
Na2CO3 + H2O -> 2Na+ + HCO3- + OH-
In this reaction, the sodium carbonate dissociates into its constituent ions, sodium (Na+) and carbonate (CO3^2-), in the presence of water. The water molecules surround and separate the sodium and carbonate ions, resulting in the formation of sodium ions (Na+), bicarbonate ions (HCO3-), and hydroxide ions (OH-).
The overall process is known as ionization or dissociation, where the solid compound breaks down into its individual ions when dissolved in water. It's important to note that the reaction occurs in an aqueous solution and not as a direct chemical reaction between solid sodium carbonate and water molecules.