ｆ．７問題，急用！！２０分！！

1. When halogen is in their elemental form (ie. X-X), it is actually non-polar in nature since you cannot find any dipole moment in teh molecule. According to the "like dissolve like" principle, they should be more soluble in non-polar solvent than polar solvent.

2. When iodine is dissolved in CHCl3 (chloroform), the iodine is just dissolved as I-I. Since there is no any chemical reaction, it stays with its original brown color. But when the iodine is dissolved in ethanol, a purple color is detected due to the formation of charged species which can be stablized by ethanol which is a kind of polar solvent.

3. The iodine can be soluble in aqueous potassium Iodide because of the fomration of I3- complex. The iodine will readily react with iodide to form I3- ion.
i.e. I- + I2 ---> I3-

4. When going down the group, the molecular weight of the halogen increases aswell as the number of electrons. Since the halogen molecule are held together by the Van der Waals' force, as the number of electron increase down the group, the degree of Van der Waals' will also increase accordingly. Because of the stronger VDW force, higher energy is need to break this intermolecular force and therefore the halogen is changed from gas to solid when going down the group.

I hope the answer can help.

1. Because there's weak van der Waals' force within halogen molecules (this weak force 'attracts' the molecules together) and there's weak der Waals' force within non-polar solvent molecules, the forces within both molecules are similar and then, non-polar solvent can dissolve halogen. Meanwhile, the weak attractive force within the polar solvent molecules and halogen molecules cannot overcome the strong dipole-dipole interaction within the polar solvent molecule, so halogen is less soluble in polar solvent.
( To Be Continued ......)

1.I think you will have more soluble.
2.I dot t no , sorry