Here's why:
* Size: Sodium ions are smaller than chloride ions. This means they experience less resistance from the surrounding water molecules as they move through the solution.
* Hydration: Both ions are hydrated, meaning they attract water molecules around them. However, sodium ions, being smaller, have a higher charge density, attracting a smaller number of water molecules compared to chloride ions. This results in a smaller hydration shell for sodium ions, making them more mobile.
* Charge: Both ions have the same magnitude of charge (+1 for Na+, -1 for Cl-), but their size difference plays a significant role in their mobility.
Therefore, sodium ions have a higher relative ionic mobility compared to chloride ions.
Important Note: This is a general statement. The actual mobility of ions can be influenced by factors like temperature, concentration, and the presence of other ions in the solution.
