How do ionic solutions conduct electricity

Water is a poor solvent, however, for hydrophobic molecules such as lipids. Nonpolar molecules experience hydrophobic interactions in water: the water changes its hydrogen bonding patterns around the hydrophobic molecules to produce a cage-like structure called a clathrate.

Thermodynamically, such a large decrease in entropy is not spontaneous, and the hydrophobic molecule will not dissolve. When electrodes are placed in an electrolyte solution and a voltage is applied, the electrolyte will conduct electricity. Use a table of standard reduction potentials to determine which species in solution will be reduced or oxidized.

Lone electrons cannot usually pass through the electrolyte; instead, a chemical reaction occurs at the cathode that consumes electrons from the anode.

Another reaction occurs at the anode, producing electrons that are eventually transferred to the cathode. As a result, a negative charge cloud develops in the electrolyte around the cathode, and a positive charge develops around the anode.

The ions in the electrolyte neutralize these charges, enabling the electrons to keep flowing and the reactions to continue. For example, in a solution of ordinary table salt sodium chloride, NaCl in water, the cathode reaction will be:.

In other systems, the electrode reactions can involve electrode metal as well as electrolyte ions. Here, the electrode reactions convert chemical energy to electrical energy. Oxidation of ions or neutral molecules occurs at the anode, and the reduction of ions or neutral molecules occurs at the cathode. Neutral molecules can also react at either electrode. For example, p-Benzoquinone can be reduced to hydroquinone at the cathode:. Hydroquinone : Hydroquinone is a reductant or electron donor and organic molecule.

Para-benzoquinone : P-benzoquinone is an oxidant or electron acceptor. The oxidized or reduced substances can also be the solvent usually water or electrodes. It is possible to have electrolysis involving gases. In order to determine which species in solution will be oxidized and which will be reduced, the standard electrode potential of each species may be obtained from a table of standard reduction potentials, a small sampling of which is shown here:. In the first beaker, distilled water does not conduct a current because water is a molecular compound.

In the second beaker, solid sodium chloride also does not conduct a current. Despite being ionic and thus composed of charges particles, the solid crystal lattice does not allow the ions to move between the electrodes. Mobile charged particles are required for the circuit to be complete and the light bulb to light up. In the third beaker, the NaCl has been dissolved into the distilled water.

Now the crystal lattice has been broken apart and the individual positive and negative ions can move. Cations move to one electrode, while anions move to the other, allowing electricity to flow see Figure below. Melting an ionic compound also frees the ions to conduct a current.

Some atoms, like sodium, have one or very few electrons in their outer shells. Other atoms, like chlorine, have outer shells that just need one more electron to have a full shell. The extra electron in that first atom can transfer to the second to fill that other shell. However, the processes of losing and gaining elections create an imbalance between the charge in the nucleus and the charge from the electrons, giving the resultant atom a net positive charge when an electron is lost or a net negative charge when one is gained.

These charged atoms are called ions, and oppositely charged ions can be attracted together to form an ionic bond and an electrically neutral molecule, such as NaCl, or sodium chloride.

The ionic bonds that keep molecules like common salt sodium chloride together can be broken apart in some circumstances. The ionic bonds can also be broken if the molecules are melted under high temperature, which has the same effect when they remain in a molten state. The fact that either of these processes leads to a collection of charged ions is central to the electrical conductivity of ionic compounds. But when they're dissociated in a solution or through melting, they can carry a current.

Dec 16, Excellent question! The short answer is that ions can only conduct electricity when they are able to move. Related questions Question 79c2f.

Question cd Why do ionic compounds dissolve in water?