The volatility of iodine, graphite and calcium chloride
Conductivity
- Conclusion
Water is polar, hexane is non-polar, and ethanol is polar but also has non-polar character.
Iodine is very volatile, soluble in hexane and ethanol and slightly soluble in water, it doesn’t conduct electricity in hexane and ethanol.
Graphite is not volatile, insoluble in water, hexane and ethanol.
Calcium chloride is volatile, insoluble in hexane, soluble in water and less soluble in ethanol, it conducts electricity in water only.
- Discussion
From the experiment 1, water and ethanol is deflected to the glass rod, It means that water and ethanol are polar liquids. Both water and ethanol have O–H bond which have a net dipole moments. When a positive charged rod is used, it is the negative ends of the dipoles in the polar molecules that are attracted towards the rod. With a negatively charged rod, the positive ends of the dipoles are attracts to it. In hexane, all the dipole moments are cancelled out and with zero resultant dipole moments, so hexane is a non-polar liquid.
In experiment 2, water and ethanol are miscible, it is because both of them are polar liquids. Water and hexane are immiscible, because water is polar but hexane is non-polar. However, hexane and ethanol are miscibility, it is because the dipole moments in ethanol is weak, so that ethanol has the properties of non-polar.
Structure of water Structure of iodine
In experiment3, iodine is soluble in hexane and ethanol but relatively insoluble in water. Iodine has covalent bond between atoms and weak intermolecular force between molecules. Iodine doesn’t conduct electricity because there is no mobile ions in the solution. Iodine has a low boiling point due to the weak van der Waal’s force, so that it is volatile.
In experiment 4, graphite is insoluble in water, hexane and ethanol. Graphite has a layered giant covalent structure, the layers are held by weak van der Waal’s forces. The giant covalent structure makes graphite insoluble in any solvent. Graphite has a high melting point due to the giant covalent structure, so that it is not volatile.
Structure of graphite
In experiment 5, calcium chloride is soluble in water and ethanol but not hexane. Calcium is an ionic compound. Ionic substances are soluble in polar solvent, e.g. water and ethanol, due to the attraction between the ion and the polar solvent molecule. They are insoluble in non-polar solvents. Although ionic compounds usually have a high boiling point, but calcium chloride carry covalent character, so that it has a low boiling point and it is volatile. Calcium chloride in water and ethanol conducts electricity in water because there are mobile ions.
