Extra 30 short questions and answers for the "Chemical Effects of Electric Current" chapter:11 of Class 8 CBSE Science:-
Q: What is an electrolyte?
A:
An electrolyte is a substance that, when dissolved in water, conducts electricity. Examples include salt solutions and lemon juice.
Q: What is electroplating?
A:
Electroplating is the process of depositing a layer of metal on another material using electricity. It is used to prevent corrosion and for decorative purposes.
Q: What happens when an electric current is passed through a conducting solution?
A:
It causes chemical changes in the solution. This is known as the chemical effect of electric current.
Q: What is the role of the anode in electrolysis?
A:
The anode is the positive electrode. It attracts negatively charged ions (anions).
Q: What is the role of the cathode in electrolysis?
A:
The cathode is the negative electrode. It attracts positively charged ions (cations).
Q: Why is distilled water a poor conductor of electricity?
A:
Distilled water lacks dissolved salts, which are necessary for conducting electricity.
Q: What is the purpose of electroplating zinc on iron?
A:
It prevents iron from rusting. This process is called galvanization.
Q: What is an LED, and how does it work?
A:
LED stands for Light Emitting Diode. It emits light when an
electric current passes
through it.
Q: What is electrolysis?
A:
Electrolysis is the process of decomposing a chemical compound by passing an electric current through it.
Q: What are the applications of electroplating?
A:
Applications include coating
jewellery
, plating car parts to prevent corrosion, and tinning food cans.
Q: What is the importance of using a magnetic compass in testing for electric current in a solution?
A:
It detects the magnetic field produced by the current, indicating its presence.
Q: Why are copper wires used in electrical circuits?
A:
Copper is a good conductor of electricity and is ductile.
Q: What is the chemical effect of electric current?
A:
It refers to the chemical changes that occur when an
electric current passes
through a conducting solution.
Q: What is the difference between a conductor and an insulator?
A:
A conductor allows electricity to pass through it, while an insulator does not.
Q: What is the role of the electrolyte in an electrolytic cell?
A:
It provides the ions necessary for the flow of electric current.
Q: What gas is released at the cathode during the electrolysis of water?
A:
Hydrogen gas is released.
Q: What gas is released at the anode during the electrolysis of water?
A:
Oxygen gas is released.
Q: What is the purpose of electrorefining metals?
A:
It is used to purify metals by electrolysis
.
Q: What are the electrodes made of in an electrolytic cell?
A:
They are made of conducting materials, often metals or graphite.
Q: What is the effect of impurities on the conductivity of water?
A:
Impurities, especially dissolved salts, increase the conductivity of water.
Q: What is the use of tin plating on food cans?
A:
It prevents the food from reacting with the iron of the can.
Q: What happens when copper
sulphate
solution is electrolyzed?
A:
Copper is deposited at the cathode.
Q: Why is it dangerous to handle electrical appliances with wet hands?
A:
Wet hands allow electricity to flow through the body, causing electric shock.
Q: What is the difference between a positive and negative terminal in a battery?
A:
The positive terminal has a higher electrical potential, and the negative terminal has a lower potential.
Q: How does an LED differ from a regular bulb?
A:
An LED consumes less energy and generates less heat compared to a regular bulb.
Q: What is the importance of using electrolytes in batteries?
A:
Electrolytes provide the medium for ion flow, enabling the battery to produce electricity.
Q: What is the function of the battery in an electrolysis setup?
A:
It provides the electric current for the chemical reactions to occur.
Q: What is the relationship between the strength of the current and the amount of metal deposited during electroplating?
A:
A stronger current results in a faster rate of metal deposition.
Q: Why is it important to clean metal objects before electroplating?
A:
Cleaning removes impurities that can interfere with the adhesion of the plating.
Q: What is the purpose of using dilute acids in some electrolysis processes?
A:
Dilute acids increase the conductivity of the solution by providing ions.
