Electrochemistry, electro + chemistry, is a branch of physical chemistry that is related to the interaction between electricity and chemical reaction. Electricity is generated when electrons or ions move, depending upon its nature of conduction whether it is a metal or an electrolyte. During the conduction of electricity through metallic conduction, both chemical reaction and transportation of matters doesn’t happen i.e. only the migration of electrons take place. While conduction of electricity through electrodes undergoes chemical changes and the transfer of ion takes place along with its matter.
While,
electrochemistry is related with those chemical reactions that: -
Electrolytic conduction is the ability of an electrolytic solution to let the electric current flow through it when the current is applied to the electrodes.
The electrolyte is an aqueous solution that conducts electricity or it can also be said as the substance that conducts electricity when dissolved in water (solvent). Only those solutions can be taken as electrolytes that can conduct electricity. Eg: - Salt-water is electrolyte as it conducts electricity while sugar + water is not an electrolyte as it cannot conduct electricity.
a. Nature of electrolyte
The degree of ionization differs with accordance to the nature of electrolyte. Ionic compounds that dissolve in water have a high degree of ionization as it ionizes almost completely while weak electrolytes ionize partially and have a very low degree of ionization.
b. Nature of solvent
The degree of ionization increases if the dielectric constant of the solvent is greater and decreases if the dielectric constant of solvent is less.
c. Dilution
If the dilution of electrolyte in the solution is increased electrolytes get ionized more completely than when it is concentrated as the equilibrium between a undissociated molecule and ions shift to the direction of ion formation. Hence, a degree of ionization increases with increase in dilution of an electrolyte.
d. Temperature
The degree of ionization increases with the increase in temperature and decreases with a decrease in temperature. Inorganic salts like NaCl, BaCl, etc. dissolve in hot water easily than in cold water.
Faraday studied about the quantitative relationship between electricity and chemical change and proposed a phenomena of electrolysis which is today known as Faraday's law of electrolysis. Faraday put forward two laws of electrolysis as: -
$$\mathcal Faraday's\;first\;law\;states\;that\;the\;mass\;of\;chemical\;substance\;discharged\;or\;deposited\\at\;the\;electrode\;is\;directly\;proportional\;to\;the\;amount\;of\;charge\;passed\;through\;the\;"electrolyte". $$
Mathematically, $$W ∝ Q$$ $$W∝I t [\because Q=I t]$$ $$W=zIt$$
Where,
z=proportionality constant known as electrochemical equivalent
I = amount of charge/current in ampere
W=mass of chemical substance
t = time in second
$$\mathcal Faraday's\;second\;law\;of\;electrolysis\;states\;that\;the\;weight\;of\;a\;chemical\;substance\\discharged\;at\;electrodes\;by\;the\;same\;quantity\;of\;electrical\;energy\;are\;directly\;proportional\;to\;their\;respective\\electrochemical\;equivalent. $$
Mathematically,$$W∝E \qquad \qquad \qquad \qquad$$ $$\qquad W=kE \qquad where,k\;is\;a\;constant$$ $$k= \frac{W}{e} \qquad \qquad \qquad \qquad$$
W= weight of a substance
E=electrochemical equivalent
References: -
(Sthapit and Pradhananga)
Sthapit, Moti Kaji, and Dr.Raja Ram Pradhananga. Foundations Of Chemistry. 5th. Vol. 1. Kathmandu: Supravaha Press, 2010. 3 vols.
https://www.youtube.com/watch?v=teTkvUtW4SA
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