The resulting solution will conduct electricity because it contains ions. It is important to keep in mind, however, that CO 2 is not an electrolyte, because CO 2 itself does not dissociate into ions. Only compounds that dissociate into their component ions in solution qualify as electrolytes. As mentioned above, when an ionizable solute dissociates, the resulting solution can conduct electricity.
Therefore, compounds that readily form ions in solution are known as strong electrolytes. By this reasoning, all strong acids and strong bases are strong electrolytes. By contrast, if a compound dissociates to a small extent, the solution will be a weak conductor of electricity; a compound that only dissociates weakly, therefore, is known as a weak electrolyte. A strong electrolyte will completely dissociate into its component ions in solution; a weak electrolyte, on the other hand, will remain mostly undissociated in solution.
An example of a weak electrolyte is acetic acid, which is also a weak acid. Nonelectrolytes are compounds that do not ionize at all in solution. As a result, solutions containing nonelectrolytes will not conduct electricity.
Dissociation of NaCl in water : When table salt NaCl is mixed in water, spheres of hydration form around the ions. Since many biomolecules are either polar or charged, water readily dissolves these hydrophilic compounds.
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:.
Standard electrode potentials table : This is the standard reduction potential for the reaction shown, measured in volts.
Positive potential is more favorable in this case. Historically, oxidation potentials were tabulated and used in calculations, but the current standard is to only record the reduction potential in tables. If a problem demands use of oxidation potential, it may be interpreted as the negative of the recorded reduction potential.
The production of this low-energy and stable electron configuration is clearly a favorable process. The following ionization is not complete,. On the other hand, ionization can be viewed as an equilibrium established for the above reaction, for which the equilibrium constant is defined as. You can generalize the definition of K here to give the equilibrium constant expression for any weak electrolyte.
The ionization or autoionization of pure water can be represented by the ionization equation. The constant K w depends on temperature. At higher temperatures, the pH is slightly less than 7, and at lower temperatures, the pH is greater than 7. Our body fluids are solutions of electrolytes and many other things.
The combination of blood and the circulatory system is the river of life , because it coordinates all the life functions. When the heart stops pumping in a heart attack, the life ends quickly.
Getting the heart restarted as soon as one can is crucial in order to maintain life. The primary electrolytes required in the body fluid are cations of calcium, potassium, sodium, and magnesium and anions of chloride, carbonates, aminoacetates, phosphates, and iodide.
These are nutritionally called macrominerals. Electrolyte balance is crucial to many body functions. Here's some extreme examples of what can happen with an imbalance of electrolytes: elevated potassium levels may result in cardiac arrhythmias; decreased extracellular potassium produces paralysis; excessive extracellular sodium causes fluid retention; and decreased plasma calcium and magnesium can produce muscle spasms of the extremities.
When a patient is dehydrated, a carefully prepared commercially available electrolyte solution is required to maintain health and well being. In terms of child health, oral electrolyte is need when a child is dehydrated due to diarrhea. The use of oral electrolyte maintenance solutions, which is responsible for saving millions of lives worldwide over the last 25 years, is one of the most important medical advances in protecting the health of children in the century, explains Juilus G.
If a parent provides an oral electrolyte maintenance solution at the very start of the illness, dehydration can be prevented. The functionality of electrolyte solutions is related to their properties, and interest in electrolyte solutions goes far beyond chemistry.
Solutions of electrolytes are always required in batteries, even in dry cells. The simplest battery consists of two electrodes. The figure here illustrates a copper-zinc battery. The left hand is a zinc electrode. The zinc atoms have a tendency to become ions, leaving the electrons behind.
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