[Physics Class Notes] on Chemical Effects of Electric Current Pdf for Exam

The flow of an electric charge between two points i.e. point A & Point B is electric current. For better understanding Imagine water in a river carrying energy from one place to another. 

An electric current is capable of producing magnetic effects and chemical effects like electrochemical reactions.

Electrons have an electric charge which causes resistors in the light bulbs and electric fires to heat up. Electrons also create magnetic fields in motors and generators.

What is the Chemical Effect of Electric Current?

The chemical reaction that takes place in a conducting solution after passing an electric current through it is called the chemical effect of electric current. 

Here are some good examples for better understanding the nature of the chemical effect of electric current.

  1. Gas bubbles are formed at electrodes.

  2. Metal deposits can be seen on electrodes

  3. Change of texture or colour of the conducting solution.

Conductor

A material, substance or object which allows free flow of electric current is a good conductor. They conduct electricity because they allow electrons to flow within them on an atom level. Conductors are known for easy transmission of light and heat.

Types of Conductor 

Conductors are mainly classified into two groups which are as follows, Good Conductors and Bad conductors.

  1. Good Conductors

Materials that allow electric current a free passage are good conductors of electricity.

  1. Bad Conductors  

Materials that do not allow electric current free passage are bad conductors of electricity.

Some examples of good conductors are metals like copper, aluminium while materials like rubber plastics are bad conductors of electricity. In the case of liquids, some liquids are good conductors of electricity while a couple of are bad conductors of electricity. The water obtained from sources like pumps, wells, ponds, and taps aren’t pure and contain several dissolved salts. Such water is a good conductor of electricity. Distilled water is free of salt and is a bad conductor of electricity.

Chemical Effects of Electric Current

Passage of current through chemical solutions causes chemical reactions to require place. Chemical effects include:

  • Formation of gas bubbles at electrodes

  • Deposition of metals at electrodes

  • Changes in solution colour

Electrolysis can be defined as the process by which ionic substances are decomposed into simpler substances when an electrical current is skilled in them.

Current Test – Conductors

Conductor

Any material that permits an electrical current to undergo it’s referred to as a conductor. Eg: metals like copper.

Insulator (Bad Conductors)

Materials that don’t allow the free flow of an electrical current through it are referred to as bad conductors or insulators. E.g: Rubber, plastic.

Electric Circuit

  • A closed-loop path which a current takes is understood as an electrical circuit.

  • When the trail of the circuit is closed, the present flows through it, but when there’s an opportunity within the path (switch is open) then, the circuit is open and is not conducting.

(Diagram)

Source of Electrical Energy 

The Source of electrical energy is the first source that allows electrons to move freely in an electric circuit. Such a source can also be called a battery. The battery consists of two terminals which are positive terminal and negative terminal. Two terminals are required for the charge to flow from one end to another. 

 

The Device in the Electric Circuit 

The second most important component is the device. it responds to the current accordingly. A device can be any object which is operated through a wall socket and used with electricity.

 

Resistance of Electricity

Resistance is the third component that every circuit has. Types of electric circuits

There are mainly two types of circuits, series circuits and parallel circuits which are easily found in homes and day-to-day devices.

 

Series Circuit 

In a series circuit, several devices can be linked in a large loop. The current that flow is the same for all the devices. The complete circuit fails if even a single device is broken.

 

Parallel Circuits

Unlike series circuits, the parallel circuit has different devices arranged in a specific manner. If a single device is broken it won’t affect the rest in the parallel circuit.

 

Tester

A tester may be a piece of electrical equipment wont to check the presence of electric current. It is usually a conductor with a led/bulb to indicate that the present is present within the circuit.

Current – Conducting Liquids

  • Liquids conduct electricity too when there are salts dissolved within the liquid

  • Solutions of acids, bases, or salts are the liquids that conduct electricity 

 

Acids, Bases, and Salts

  • Acids and bases are chemical substances that dissociate to make ions when dissolved during a solution. They are loyal conductors of electricity because of the presence of ions.

  • Water when dissolved in salt also conducts as they release positive/negatively charged ions.

Acids

Acidic substances are very sour in taste. We are surrounded by many acids. Fruits like lemon and oranges contain citric acid.

The term acid is taken from the Latin word ‘acidus’. Acidus means sour. Acid turns blue litmus paper red but red litmus paper remains unchanged when dipped in acid.

Bases

Bases taste bitter and feel soapy. red litmus paper turns blue when in contact with the base but blue litmus paper remains unchanged. Household bleach is a very good example of base. 

Salts

Common salt is the end product of the reaction between acid and base.

Conduction of Electricity in the Water

  • Distilled water may be a bad conductor of electricity due to the absence of dissolved salts and minerals.

  • Water starts conducting when acids, bases, or salts are dissolved that releases ions, which conduct when a possible difference is applied.

(Diagram)

 

Electrodes and Electrolyte

  • A conductor, when immersed during a solution with its end connected to the terminals of a battery, thereby completing a circuit, is named an electrode. There are usually 2 electrodes→ cathode(ve) and anode(+ve).

  • An electrolyte is a solution in which the electrodes are submerged. They dissociate on the passage of electric current.

  • The electrodes, electrolyte, and therefore the battery together form the electrochemical/electrolytic cell.

Electroplating

  • When electricity is used to deposit a layer of the desired metal to another metal, that process is termed Electroplating. 

  • Example: Using copper sulfate solution as electrolyte and copper electrodes. Copper is electroplated on the negative electrode. The cubic inch answer is replenished thanks to the addition of copper ions from the positive electrode.

(Diagram)

 

Applications of Electroplating

  • Coating zinc on the iron to prevent corrosion and rust.

  • Coating silver and gold for jewellery.

  • Coating tin onto iron for cans as tin is a smaller amount reactive than iron.

  • Chromium coating for car parts, bath fittings because it features a shiny appearance.

 

Do you know?

The first power plant was established in 1882 by Thomas Edison. The power station was able to provide electricity to 85 buildings.

 

Learn what happens when electricity passes through different conductors. Understand how different changes occur in those conducting mediums and develop our concepts accordingly. 

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