Please enable JavaScript.
Coggle requires JavaScript to display documents.
APPLICATIONS OF THE OXIDATION-REDUCTION PROCESS - Coggle Diagram
APPLICATIONS OF THE OXIDATION-REDUCTION PROCESS
OXIDATION-REDUCTION CONCEPT
An oxidation-reduction consists of two half-reactions that occur through an electron transfer. These reactions are called
redox
.
Oxidation
is defined as a loss of electrons.
Reduction
, as an electron gain.
CONCEPT OF OXIDIZING AGENT AND REDUCING AGENT :
OXIDIZING AGENT
It is the chemical species in a redox process that accepts electrons and, therefore, is reduced in the process.
-Gains electrons -Decreases its oxidation number
REDUCING AGENT
Chemical species in a redox process that loses electrons, therefore, oxidizes in this process (the oxidation number increases).
-Loses electrons -increases its oxidation number
OXIDATION NUMBER
Redox reactions are not always so simple, and it becomes necessary to assign charges to the different atoms of the species involved.
Rules for assigning oxidation numbers to elements
The oxidation state or number of an element in a fundamental or uncombined state is zero.
The oxidation number of hydrogen (H) is +1, except in metal hydrides (compounds formed by H and a metal), where it is - 1; for example, NaH, CaH2.
Oxygen's oxidation number is - 2, except for peroxides, where it is - 1.
In combined alkali metals it is +1; in combined alkaline earth metals, it is +2, and combined aluminum it is +3.
The oxidation number of the monoatomic ions coincides with the charge of the ion. For example, the oxidation number of CI- is - 1.
The algebraic sum of the oxidation numbers of the elements in a compound is zero.
The algebraic sum of the oxidation numbers of the elements of a polyatomic ion is equal to the charge of the ion.
In addition, in covalent compounds, the negative oxidation number is assigned to the most electronegative atom, and all others are positive.
IDENTIFICATION OF OXIDATION-REDUCTION USING OXIDATION NUMBERS
Oxidation numbers are used to identify what is oxidized and what is reduced in a reaction. In oxidation, the loss of electrons increases the oxidation number, so that it is greater (more positive) in the product than in the reagent; and in reduction, the gain of electrons decreases the oxidation number, so it is lower (more negative) in the reaction product.
BALANCING OXIDATION-REDUCTION REACTIONS
The two methods most commonly used are the
ion-electron method
and the
oxidation - number- changed method.
ion-electron method
It is used for reactions where the oxidation-reduction process occurs in a solution. This method is so called because ions, from the participating substances such as reducing and oxidizing agents, and electrons appear
oxidation - number- changed method.
Is based on changes in the oridation numbers of the species that react.
ELECTRIC ENERGY AND OXIDATION-REDUCTION
GALVANIC OR VOLTAIC
They are devices capable of generating an electric current from a spontaneous chemical reaction of oxidation-reduction.
ELECTROLYTIC CELLS
Is an electrochemical cell in which electrical energy is used to drive a non-spontaneous oxidation-reduction reaction.
APPLICATIONS OF ELECTROCHEMICAL REACTIONS
ELECTRIC BATTERIES
Car batteries
The storage battery of a car consists of six lead cells linked in series, with a total voltage of 12 volts. The positive electrode is lead dioxide and the negative electrode is immersed in a sulfuric acid solution. The battery status is checked by the density of the electrolyte: a low density indicates that the concentration of sulfuric acid is low and the battery is partially discharged.
There are several types of batteries.
Alkaline batteries
Secondary or storage batteries
Dry batteries
METALLIC COATINGS, ELECTROPLANTING
Electroplating consists of applying a thin layer of metal on an electric current conducting surface: chrome plating gives metals a shiny surface, steel is galvanized with zinc to protect it from corrosion. Metals are plated or gilded by electroplating.
MOLTEN NACI ELECTROLYSIS
Is widely used in industry to obtain sodium and chlorine in its elemental state, since both elements are not found as such in nature due to their high chemical reactivity. The process is carried out in a device called an electrolytic vat, using molten sodium chlorides raw material or supersaturated solutions of sodium chloride
