1. In this paper chromatography experiment,
- The mobile phase is composed of water.
- The stationary phase is composed of paper.
2. The major intermolecular force between the charged species and the partial charge of a molecule with a permanent dipole is ion-dipole interactions.
3. Explanation of why the hydrated ionic radius is different for each cation:
The hydrated ionic radius is different for each cation due to differences in charge density. Charge density is determined by the charge of the ion and its size. Specifically, smaller ions with higher charges have higher charge densities and can attract water molecules more strongly. This attraction affects the amount of water molecules that surround the ion, thereby altering the hydrated ionic radius.
In the given context:
- Fe²⁺ (0.55 pm): This ion has a relatively high charge density, leading to a stronger attraction to water molecules, which results in a smaller hydrated radius.
- Co²⁺ (0.75 pm): This ion has a lower charge density compared to Fe²⁺, leading to a weaker attraction to water molecules, resulting in a larger hydrated radius.
- Cu²⁺ (0.65 pm): This ion has charge density and a hydrated radius intermediate between Fe²⁺ and Co²⁺.
Thus, the different charge densities of the cations (Fe²⁺, Co²⁺, Cu²⁺) affect their ability to attract water molecules, which in turn determines the size of the hydrated ionic radius in solution.
