Factors Affecting Electrolysis

The passing of direct current through an electrolyte solution produces a chemical reaction at each electrode, causing the decomposition of the material to obtain the desired product, otherwise known to be electrolysis. The major components of this process are electrolytes, electrodes and an external power source. The two electrodes are set up in two different containers of electrolytes that are connected by the salt bridge or otherwise can be called an ion-exchange membrane that keeps the products from diffusing to the vicinity of the opposite electrode.

An electrolyte is a chemical solution containing free ions responsible as charge carriers. The state of the electrolytes needs to be in liquid to ensure the undergoing of the process of electrolysis as otherwise in case of solid where the mobility of ions is not possible won’t contribute really to the further proceeding of the process. The electrodes are kept apart from each other such that the current flowing takes place through the electrolyte and the power source that completes the electric circuit. A dc supplied by the source drives the reaction causing ions in the electrolyte to be repelled by like charges and attracted toward the respective oppositely charged electrode.

Process of Electrolysis

The major process of electrolysis is the interchange of atoms and ions by the addition or removal of charge carriers due to the applied current. The quantity of the products formed is proportional to the current flown. When two or more electrolytic cells are connected in series to the same voltage source, the products produced in the cells are proportional to their respective equivalent weight. Faraday’s laws of electrolysis govern these calculations. Each electrode attracts ions of opposite charges. Cations move towards the electron-providing (cathode), whereas anions move towards the electron-extracting (anode). As a result of this process, electrons are released at anode and consumed at the cathode. The gain of electrons is considered a reduction, and loss of the same is considered oxidation. When neutral atoms or molecules, like those present on the surface of an electrode, gain or lose electrons and they contribute to ions or chemical reactions with other ions. When an ion accepts or rejects electrons and becomes neutral, it will form compounds that separate from the electrolyte. When an ion loses or accepts an electron without being neutral, its electric charge is altered in the process. 

Decomposition Potential or Decomposition Voltage

The minimum voltage between anode and cathode of an electrolytic cell is a part of the electrolysis procedure. The voltage at which electrolysis is thermodynamically preferred is the difference in the Nernst equation’s electrode potentials. The rate of reaction involved in the electrolysis process can be manipulated by applying more voltage to the circuit, whereas the vice-versa is not feasible.

Oxidation and reduction at the electrodes

Oxidation and reduction of ions or neutral molecules occur at anode and cathode, respectively. 

Variation of energy in electrolysis process 

The amount of electrical energy that must be added equals the change in Gibbs free energy of the reaction plus the losses in the system. 

Factors Affecting Electrolysis

Factors Affecting Products of Electrolysis are as follows

i. Products of electrolysis depend on the material or nature being electrolyzed, i.e. the nature and concentration of electrolyte govern the process of electrolysis. The process is faster for a strong electrolyte, whereas it is slower for a weaker electrolyte. Thus an extra potential said as over-potential is necessary where the extra amount depicts the rate of reaction involved.

ii. It also depends on the nature of electrodes. That is, in the case of the inert electrode, it doesn’t participate in the reaction, whereas if the electrode used is reactive in nature, then it takes part in the reaction.

iii. Presence of various oxidizing and reducing agents present in the electrolytic cell manipulate electrolysis products.

iv. It depends upon standard electrode potentials of the different oxidizing and reducing species present in the electrolytic cell. 

v. In the case of multiple reactions, it depends on the standard electrode potential of various reactions taking the place of which the reduction reaction, which has the highest value of standard electrode potential, occurs at the cathode. And similarly, the oxidation reaction, which has the lowest value of standard electrode potential, takes place at the anode.

Conclusion

Electrolysis is a technique of separation of naturally occurring elements from the ores, or other sources available through direct current to drive a non-spontaneous chemical reaction is said to be electrolysis. The major components of this process are electrolytes, electrodes, a salt bridge and an external power source. The factors affecting the electrolysis process are the nature and material of the electrode, the presence of oxidizing and reducing agents in the electrolyte, and electrode potential. The help of the Nernst equation gives the thermodynamically preferred voltage required for the feasibility of the chemical reaction, and the additional electrical energy required is given by Gibbs energy.