Physics Chemical Effects of Current Part 12 (Questions) Class 8 VIII

TL;DR

This video discusses the chemical effects of electric current, including conducting liquids, electroplating, and the conduction of water and rainwater.

Transcript

hello friends this video on chemical effects of current part 12 is brought to you by exam for calm no more tear from exam so with this we have reached towards the end of this lesson so it is time to look at some of the questions so let us look at question number 1 fill in the blanks most liquids that conduct electricity are solutions of so what did... Read More

Key Insights

• 👋 Liquids that contain acids, bases, or salts are good conductors of electricity.
• 🤘 Passing an electric current through a solution causes chemical changes, such as the deposition of metal in electroplating.
• 👋 The deflection of a magnetic needle in a conducting solution confirms its good conductivity.
• 💦 Pure water does not conduct electricity, but it can be made conductive by adding salts or acids.
• 👋 Rainwater and seawater are good conductors due to the presence of dissolved salts.
• 🫢 Presence of water during electrical repairs poses a risk of electric shock.
• 🌊 Deflection of a compass needle in sea water indicates its better conductivity compared to drinking water.
• 🧂 Rainwater contains dissolved salts and conducts electricity, causing the compass needle to deflect.

Questions & Answers

Q: What makes a liquid a good conductor of electricity?

Liquids that contain acids, bases, or salts are generally good conductors of electricity. For example, lemon juice and sodium chloride solutions are good conductors due to their chemical composition.

Q: What is electroplating and why is electricity important in the process?

Electroplating is the process of depositing a layer of metal onto another material using electricity. Electric current flowing through the solution allows for the transfer of ions and the deposition of the desired metal, making electricity essential in the process.

Q: Why does a magnetic needle in a tester show deflection in a conducting solution?

When a current flows through a conducting solution, such as in the tester, the magnetic needle deflects, indicating that current is flowing through the circuit. This deflection confirms that the solution is a good conductor.

Q: Why do firemen shut off the main electrical supply before using water hoses during a fire?

Normal water, which is a good conductor of electricity, can increase the risk of electric shock if it comes into contact with electric appliances. To prevent this, firemen shut off the main electrical supply before using water hoses to minimize the chances of electric shock.

Q: Can pure water conduct electricity, and how can it be made conductive?

Pure water, without any impurities, does not conduct electricity. To make water conductive, salts or acids can be added to it. Tap water, seawater, or saltwater can all conduct electricity due to the presence of dissolved salts.

Q: Why is it unsafe for an electrician to carry out electrical repairs outdoors during heavy downpours?

Rainwater contains dissolved salts and conducts electricity. If an electrician performs repairs outdoors during heavy rain, there is a higher chance of electric shock when water comes into contact with electric wires or appliances.

Q: Why does a compass needle deflect more in sea water compared to drinking water?

Sea water contains salts, acids, or bases, which are better conductors of electricity. The greater deflection of the compass needle in sea water demonstrates that sea water is a better conductor of electricity compared to regular drinking water.

Q: Why does rainwater cause the compass needle to deflect?

Rainwater contains dissolved salts, which allow it to conduct electricity. Unlike distilled water, which is a poor conductor, rainwater conducts electricity and causes the compass needle to deflect.

Q: How can copper be purified through electroplating?

To purify copper, a thin plate of pure copper and a thick rod of impure copper are used as electrodes. The impure copper rod is attached to the positive terminal of a battery, and as electric current passes through the solution, copper ions from the impure rod move to the thin copper plate, resulting in the pure copper being deposited on the negative electrode.

Summary & Key Takeaways

• The video explores the conductivity of liquids, such as acids, bases, and salts, and how they can conduct electricity.

• It explains the chemical changes that occur when an electric current passes through a solution, including the process of electroplating.

• The video discusses how a tester can be used to determine if a solution is a good conductor, and the reasons why water and electricity should be kept separate to avoid electric shock.