Online Test — Chemical Effects of Electric Current
25 Questions • 15 min • Chapter MCQ
15:00
Question 1 of 25
A liquid that conducts electricity is called a/an:
Insulator
Electrolyte
Conductor metal
Vacuum
Explanation: A conducting liquid (solution) is called an electrolyte.
Question 2 of 25
Liquids conduct electricity because they contain free:
Atoms only
Ions
Electrons in metal
Molecules of gas
Explanation: Free ions in the liquid carry the electric current.
Question 3 of 25
In a conduction tester, a liquid conducts if the:
Bulb does not glow
Bulb glows
Battery melts
Wire breaks
Explanation: If the liquid conducts, current flows and the bulb glows.
Question 4 of 25
Which of these does NOT conduct electricity?
Salt solution
Dilute acid
Distilled water
Lemon juice
Explanation: Distilled (pure) water lacks free ions, so it does not conduct well.
Question 5 of 25
An LED is used instead of a bulb because it can detect a:
Strong current only
Very weak current
Magnetic field
High voltage only
Explanation: An LED can light up with even a very weak current.
Question 6 of 25
The decomposition of a conducting liquid by an electric current is called:
Reflection
Electrolysis
Evaporation
Distillation
Explanation: Electrolysis is the decomposition of a conducting liquid by an electric current.
Question 7 of 25
The electrode connected to the positive terminal of the battery is the:
Cathode
Anode
Resistor
Filament
Explanation: The anode is the positive electrode (connected to the + terminal).
Question 8 of 25
In the electrolysis of water, the gas released at the cathode is:
Oxygen
Hydrogen
Carbon dioxide
Nitrogen
Explanation: Hydrogen is released at the cathode (negative electrode).
Question 9 of 25
In the electrolysis of water, the gas released at the anode is:
Hydrogen
Oxygen
Helium
Chlorine
Explanation: Oxygen is released at the anode (positive electrode).
Question 10 of 25
When copper sulphate solution is electrolysed, copper is deposited on the:
Anode
Cathode
Wire
Battery
Explanation: Copper is deposited on the cathode (negative electrode).
Question 11 of 25
Electroplating is the process of depositing a thin layer of one ______ over another object.
Gas
Metal
Liquid
Plastic
Explanation: Electroplating deposits a thin layer of metal over an object using current.
Question 12 of 25
In electroplating, the object to be coated is connected as the:
Anode
Cathode
Battery
Switch
Explanation: The object to be coated is made the cathode (negative electrode).
Question 13 of 25
Tin is electroplated onto iron to make food cans because tin:
Rusts quickly
Does not rust easily and is non-toxic
Is poisonous
Is magnetic
Explanation: Tin resists rusting and is non-toxic, protecting the iron and the food.
Question 14 of 25
Jewellery is often electroplated with gold or silver to:
Make it heavier
Give an attractive, valuable look cheaply
Make it rust
Conduct electricity
Explanation: Plating gives cheap jewellery the attractive look of precious metals cheaply.
Question 15 of 25
An advantage of electroplating is that it:
Causes rusting
Protects metals from corrosion
Removes shine
Weakens the object
Explanation: Electroplating protects metals from rusting and corrosion.
Question 16 of 25
The amount of metal deposited in electrolysis depends on the current and the:
Colour
Time of current flow
Temperature of the room
Size of the wire only
Explanation: The deposit depends on the strength of the current and the time it flows.
Question 17 of 25
If a larger current is passed for the same time, the metal deposited will be:
Less
More
The same
Zero
Explanation: A larger current deposits more metal in the same time.
Question 18 of 25
If the current flows for a longer time, the metal deposited will be:
Less
More
The same
None
Explanation: A longer time of current flow deposits more metal.
Question 19 of 25
To get a thicker coating in electroplating, one should use:
Smaller current, shorter time
Larger current, longer time
No current
A magnet
Explanation: A larger current for a longer time deposits more metal (thicker coating).
Question 20 of 25
This principle lets manufacturers control the ______ of the electroplated coating.
Colour only
Thickness
Smell
Sound
Explanation: By adjusting current and time, the coating thickness can be controlled.
Question 21 of 25
Which of these is NOT an effect of electric current?
Heating effect
Magnetic effect
Chemical effect
Gravitational effect
Explanation: Current produces heating, magnetic, and chemical effects, not a gravitational effect.
Question 22 of 25
The chemical effect of current occurs when current passes through a:
Solid metal wire
Conducting liquid
Vacuum
Magnet
Explanation: The chemical effect occurs in conducting liquids (electrolytes).
Question 23 of 25
A sign of the chemical effect of current in a liquid is:
The wire melting
Gas bubbles at the electrodes
A loud sound
A bright flash only
Explanation: Gas bubbles, metal deposits, and colour changes show the chemical effect.
Question 24 of 25
The heating effect of current is used in:
Electroplating
Electric heaters
A compass
A magnet
Explanation: The heating effect is used in electric heaters, irons, and bulb filaments.
Question 25 of 25
Besides electroplating, the chemical effect of current is used industrially to:
Cool metals
Extract and purify metals
Produce sound
Reflect light
Explanation: The chemical effect is used to extract and purify metals on a large scale.