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Chemical Effects of Electric Current — Class 8 CBSE Science MCQs with Solutions
Free Class 8 CBSE Science Chemical Effects of Electric Current MCQs with step-by-step solutions. Practise online on Prepizo — no login needed.
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Sample questions with solutions
Q1 — easy
Which liquid is a good conductor of electricity?
A. distilled water
B. salt solution ✓ Correct
C. kerosene
D. vegetable oil
Solution: Dissolved salt provides free ions.
Q2 — easy
Pure distilled water is a:
A. good conductor
B. poor conductor ✓ Correct
C. metal
D. gas
Solution: It has almost no free ions.
Q3 — easy
The process of depositing a layer of metal on another using electricity is:
A. electroplating ✓ Correct
B. galvanising by heat
C. welding
D. melting
Solution: Electroplating uses electric current.
Q4 — easy
A simple tester glows when the circuit is:
A. broken
B. complete ✓ Correct
C. wet only
D. empty
Solution: Current flows only in a complete circuit.
Q5 — hard
During electrolysis of water, hydrogen and oxygen are collected in the ratio:
A. 1 : 1
B. 2 : 1 ✓ Correct
C. 1 : 2
D. 3 : 1
Solution: Water is H₂O, so twice as much hydrogen forms.
Q6 — hard
A tester using an LED instead of a bulb is more sensitive because an LED:
A. needs a very large current
B. glows even with a weak current ✓ Correct
C. needs no current
D. produces heat
Solution: LEDs light up at very low currents.
Q7 — hard
The chemical effect of current is NOT shown by:
A. copper sulphate solution
B. lemon juice
C. salt water
D. dry wooden block ✓ Correct
Solution: Dry wood does not conduct electricity.
Q8 — medium
During electrolysis of water, the gas collected at the negative electrode is:
A. oxygen
B. hydrogen ✓ Correct
C. nitrogen
D. chlorine
Solution: Hydrogen collects at the cathode.
Q9 — medium
Chromium plating on car parts is done to:
A. increase weight
B. prevent corrosion and give shine ✓ Correct
C. reduce cost only
D. make it magnetic
Solution: Chromium resists corrosion and looks bright.
Q10 — medium
In electroplating, the object to be plated is connected to the:
A. positive terminal
B. negative terminal ✓ Correct
C. either terminal
D. no terminal
Solution: The object acts as the cathode.
Q11 — medium
Which is used as a cheaper base metal for silver-plated ornaments?
A. gold
B. copper or nickel ✓ Correct
C. platinum
D. diamond
Solution: A cheaper metal is coated with a thin silver layer.