Conductivity Of A Solution Containing Ions

The two support wires for the filament of a broken light bulb serve as electrodes.When the electrodes are immersed in a solution and current flows through the solution the light bulb glows.That is, the electrodes serve as a switch for the circuit. Current flows through the solution only when ions are present.

The Melting Points Of Molecular Vs Ionic Compounds

Only the heat from a match is required to melt naphthalene, a covalent molecular compound, whereas a butane torch, capable of reaching temperatures above 600 °C, is required to melt sodium bromide. Notice that at the beginning of the heating of the sodium bromide some condensation appears on the walls of the test tube. This is water of hydration and is driven from the sodium bromide at around 100 °C.

The Difference In Solubilities Of Molecular And Ionic Compounds

The test tubes contain water (far left and second from the right) and hexane (second from the left and far right). Water is a polar solvent whereas hexane is a nonpolar solvent. Naphthalene, a covalent molecular compound, is insoluble in water even with stirring but dissolves easily in hexane (second from left). Sodium bromide, an ionic compound, dissolves easily in water but is insoluble in hexane (it settles to the bottom and is difficult to see in the test tube on the right).