  Chemistry

## formula

### Electrical Units of Charge

Following are the units of charge.
• Coulomb : Coulomb is the smaller unit of charge or electricity . The amount of charge that passes a given point when 1A current flows for 1 s.
• Faraday : The amount of electric charge on one mole of electron is called as Faraday.

## law

The amount of substance that undergoes a chemical reaction at an electrode during electrolysis is proportional to the quantity of electricity passed through an electrolyte.

is the weight of the substance
is the amount of charge passed
is current
is time for which current flows
is proportional constant.

The mass of a substance deposited or liberated at any electrode on passing a certain amount of charge is directly proportional to its chemical equivalent weight.

Where,
and are weight deposited of two elements 1 and 2 respectively
and are the equivalent weights of two elements 1 and 2 respectively.

## example

### Numerical on Faraday's First Law

Question: When of charge is passed through solution, g of copper is deposited. How much charge should be passed through the solution to deposit g of copper?
Solution: According to Faraday's First Law,
First Case:
Second Case: , is a charge to deposit g of copper.
Dividing first case by second one
We get,

## law

### Faraday's Second Law of Electrolysis

Faraday's Second Law of Electrolysis states that the mass of a substance deposited or liberated at any electrode on passing a certain amount of charge is directly proportional to its chemical equivalent weight.

Where,
and are weight deposited of two elements 1 and 2 respectively
and are the equivalent weights of two elements 1 and 2 respectively.

## result

### Combination of Two Faraday's Law

By the passage of 1 mole of electrons , the equivalent weight of a substance is deposited or liberated.
This is a combined Faraday's Law of Electrolysis.

## example

### Numerical on Faraday's Second Law

Question: A certain quantity of electricity is passed through an aqueous solution of  and cupric salt solution connected in series. The amount of silver deposited is g. The amount of copper deposited is:
(Atomic wt. of g/mole)
Solution:
Equivalent weight of silver g/eq
Equivalent weight of copper g/eq
Mass of deposited g
Substitute values in the following equation,

g.

## definition

### Define Electrolysis

Electrolysis refers to the decomposition of a substance by an electric current.

Example: When the current is passed through the molten sodium chloride, sodium and chlorine are deposited at different electrodes. Thus, sodium chloride is decomposed into sodium and chlorine

## definition

### Define and explain electrolysis

Electrolysis is the process by which electric current is passed through a substance to effect a chemical change. The chemical change is one in which the substance loses or gains an electron (oxidation or reduction). The process is carried out in an electrolytic cell, an apparatus consisting of positive and negative electrodes held apart and dipped into a solution containing positively and negatively charged ions. The substance to be transformed may form the electrode, may constitute the solution, or may be dissolved in the solution. Electric current (i.e., electrons) enters through the negatively charged electrode (cathode); positively charged components of the solution travel to this electrode, combine with the electrons, and are transformed to neutral elements or molecules. The negatively charged components of the solution travel to the other electrode (anode), give up their electrons, and are transformed into neutral elements or molecules. If the substance to be transformed is the electrode, the reaction is generally one in which the electrode dissolves by giving up electrons.