Every question from this NCERT chapter, with a detailed explanation.
In the electrolysis of acidified water, as demonstrated by William Nicholson, the gas bubbles evolved at the positive electrode (anode) and negative electrode (cathode) are, respectively:
Consider the following statements regarding the "Potato Experiment": 1. It demonstrates that vegetables like potatoes can conduct electricity. 2. A greenish-blue spot appears around the wire connected to the negative terminal. 3. This effect can be used to identify the positive terminal of a concealed battery. Which of the statements given above are correct?
Which one of the following phenomena is NOT a direct result of the chemical effect of electric current?
Liquids that conduct electricity are typically solutions containing:
The passage of electric current through water containing a small amount of sodium chloride results in:
The primary reason tap water conducts electricity while distilled water acts as an insulator is the presence of:
In the context of an electrolytic cell, the term 'electrodes' refers to:
In an experiment involving the passage of current through a potato, a greenish-blue spot appears around the positive wire. If the battery polarity is reversed, what is the expected observation?
Who among the following scientists is credited with demonstrating that the passage of electric current through water causes it to decompose into hydrogen and oxygen?
With reference to the process of electroplating, consider the following statements: 1. Electroplating is the process of removing a metal layer using electricity. 2. The object to be coated is connected to the negative terminal of the battery. 3. The metal to be deposited is connected to the positive terminal of the battery. Which of the statements given above is/are correct?
Which of the following pairs is correctly matched regarding electroplating applications?
When an electric current passes through an aqueous copper sulphate solution, the compound dissociates into:
Which one of the following is a significant environmental challange associated with the electroplating industry
Consider the following statements regarding the conduction of electricity in liquids: 1. Most liquids that conduct electricity are solutions of acids, bases, or salts. 2. Dissolving common salt in distilled water makes it an insulator. 3. Distilled water becomes a conductor if lemon juice is added to it. Which of the statements given above is/are correct?
During the electroplating of copper, the net transfer of copper occurs in which direction?
Consider the following statements about the conductivity of water: 1. Rainwater is chemically pure and does not conduct electricity. 2. Tap water conducts electricity because it contains dissolved mineral salts. Which of the statements given above is/are correct?
It is dangerous to touch electrical appliances with wet hands primarily because:
The magnetic effect of electric current is utilized in testing electrical conduction in liquids primarily because:
In an electroplating circuit, if the metal object to be plated is inadvertently connected to the positive terminal (anode), the likely consequence is that:
Consider the following statements regarding the setup for electroplating copper: 1. The electrolyte used is a solution of Zinc Sulphate. 2. The anode (positive terminal) is made of pure copper. 3. The cathode (negative terminal) is the object to be plated. Which of the statements given above are correct?
Which one of the following liquids acts as an electrical insulator?
During the electrolysis of water, the gas evolved at the anode (positive terminal) is:
Consider the following statements about the conductivity of air: 1. Air is a good conductor of electricity under normal conditions. 2. During lightning, electric current passes through air. 3. Air is classified as a poor conductor rather than an insulator. Which of the statements given above is/are correct?
Which of the following is a potential application of the chemical effect of electric current?
Consider the following statements about the conductivity of liquids: 1. Pure water is a good conductor of electricity. 2. Water containing dissolved salts is a good conductor. 3. Liquids that conduct electricity are known as insulators. Which of the statements given above is/are correct?
What is the primary scientific reason for coating electrical wires with materials such as plastic or rubber?
In an electrolytic cell used for electroplating, what is the immediate consequence of disconnecting the external power source?
When testing the electrical conductivity of a liquid using a simple circuit, the bulb glows dimly. What is the most likely reason for this observation?
Consider the following statements regarding the chemical effects of electricity: 1. The process of electroplating is an application of the chemical effect. 2. The decomposition of water into oxygen and hydrogen is an application of the heating effect. Which of the statements given above is/are correct?
In the process of electroplating a layer of silver onto a copper spoon, which one of the following arrangements is correct?
What is the primary function of the battery (DC source) in an electroplating circuit?
Consider the following statements regarding the safety of electrical repairs: 1. It is safe for an electrician to carry out electrical repairs outdoors during heavy rain. 2. Rainwater is a good conductor of electricity. Which of the statements given above is/are correct?
Consider the following statements regarding the electroplating of copper: 1. Copper is transferred from the positive electrode to the negative electrode. 2. The concentration of the solution decreases rapidly as copper is deposited. 3. The process requires a direct current source (battery). Which of the statements given above is/are correct?
Chromium plating is widely used on car parts and bath taps. However, objects are not made entirely of chromium primarily because:
Which of the following solutions will conduct electricity? 1. Lemon Juice 2. Vinegar 3. Distilled Water 4. Vegetable Oil Select the correct answer using the code given below:
With reference to the electrical properties of liquids, what happens when common salt is dissolved in distilled water?
In the process of electroplating copper, what is the effect on the copper plate connected to the positive terminal of the battery?
Which one of the following is not a primary objective of the industrial process of electroplating?
Which one of the following substances, when dissolved in distilled water, does not significantly increase its electrical conductivity?
Consider the following statements regarding water and conductivity: 1. Water obtained from taps usually conducts electricity. 2. Dissolved mineral salts make water a perfect insulator. 3. Distilled water is free of salts and is a poor conductor. Which of the statements given above are correct?
In detecting electric current through weakly conducting liquids, a magnetic compass is often preferred over a standard bulb tester because:
Consider the following statements about the heating effect of electric current: 1. The glowing of a bulb in a tester is due to the magnetic effect of current. 2. If the current is weak, the filament may not get heated sufficiently to glow. 3. Liquids that conduct electricity may produce a current too weak for a standard bulb. Which of the statements given above is/are correct?
Which one of the following sets of liquids consists entirely of electrical conductors?
With reference to the chemical effects of electric current, consider the following statements: 1. Passing electric current through solutions causes only physical changes, not chemical. 2. The formation of gas bubbles on electrodes is a possible indication of a chemical effect. 3. A change in the colour of the solution is not a chemical effect of electric current. Which of the statements given above is/are correct?
Consider the following statements regarding the conductivity of liquids: 1. Rubber and plastic are poor conductors of electricity. 2. Liquids like lemon juice and vinegar are poor conductors of electricity. 3. The water from a hand pump is a good conductor of electricity. Which of the statements given above is/are correct?
Tin is used for electroplating iron containers for food storage primarily because:
Consider the following statements about the disposal of conducting solutions from electroplating factories: 1. Conducting solutions can be safely released into water bodies without treatment. 2. They are considered polluting waste. 3. Specific disposal guidelines exist to protect the environment. Which of the statements given above is/are correct?
With reference to the electrical conductivity of materials, consider the following statements: 1. Insulators do not easily allow electric current to pass through them. 2. Air is a perfect insulator and never conducts electricity. 3. It is more appropriate to classify materials as ‘good conductors’ and ‘poor conductors’ rather than ‘conductors’ and ‘insulators’. Which of the statements given above is/are correct?
Which one of the following liquids serves as an electrolyte and would cause a magnetic compass needle to deflect in a closed electric circuit?
Consider the following statements regarding the use of an LED (Light Emitting Diode) in an electric tester: 1. LEDs require a very high current to glow compared to standard bulbs. 2. The longer lead of the LED is connected to the positive terminal of the battery. 3. The shorter lead of the LED is connected to the negative terminal of the battery. Which of the statements given above is/are correct?
Why might an electric bulb fail to glow in a liquid tester circuit even if the liquid is conducting electricity? 1. The current flowing through the circuit is too weak to heat the filament sufficiently. 2. The connections in the circuit are tight and secure. 3. The bulb filament is intact. Select the correct answer using the code given below:
With reference to the magnetic effect of electric current, consider the following statements: 1. A magnetic compass cannot detect weak electric currents. 2. The deflection of the magnetic needle depends on the magnitude of the current flowing in the wire. Which of the statements given above is/are correct?
In the process of electroplating copper using a copper sulphate solution, the copper anode (positive terminal) serves to:
Why is chromium plating done on objects like car parts and bath taps? 1. Chromium has a shiny appearance. 2. Chromium does not corrode. 3. Chromium is easily scratched. 4. Chromium is significantly cheaper than iron. Select the correct answer using the code given below:
Consider the following statements regarding the electroplating of tin onto iron for making cans: 1. Tin is more reactive than iron. 2. Tin plating prevents food from coming into contact with iron. 3. Tin provides the structural strength to the can. Which of the statements given above is/are correct?
Galvanization involves the deposition of a zinc layer on iron objects. The primary purpose of this process is to:
In a copper electroplating setup, if the copper cathode (negative electrode) is replaced by a carbon rod, which one of the following will occur?
The phenomenon where the passage of an electric current through a conducting liquid induces a chemical change is known as:
Consider the following statements about LEDs: 1. They are preferred over bulbs in testers for detecting weak currents. 2. LEDs can be connected to the circuit in any direction without checking polarity. 3. They consume significantly more electricity than standard bulbs. Which of the statements given above is/are correct?
In the electrolysis of water, a few drops of dilute sulphuric acid are often added to the water in order to:
Match List I with List II and select the correct answer using the code given below: List I | List II A. Chromium | 1. Protects iron from rust B. Tin | 2. Shiny appearance and scratch resistant C. Zinc | 3. Used for storing food D. Gold | 4. Appearance of expensive metal
The formation of a greenish-blue spot around the positive electrode inserted into a potato is an indication of the:
The glowing of the filament in an incandescent bulb used in a simple electric tester is caused by the:
With reference to the chemical effects of currents, consider the following statements: 1. Metal deposits never occur on electrodes during electrolysis. 2. The reaction depends on the type of solution and electrodes used. 3. All chemical effects invariably result in the production of gas bubbles. Which of the statements given above is/are correct?
The deflection of a magnetic compass needle placed near a wire carrying current through a liquid indicates that the liquid is:
When testing the conduction of electricity through a potato, which one of the following effects is typically observed?