Class 8 Chemical Effects Of Electric Current CBSE Questions & Answers

Class 8 · Chemical Effects Of Electric Current

This is Science Class 8 Chemical Effects of Electric Current CBSE Questions & Answers. There are 15 questions in this test with each question having around four answer choices.

Questions & Answers

1
Chemical effect of electric current is used in
  • A
    Heating
  • B
    Magnetizing
  • C
    Lighting
  • D
    Electroplating
    Correct
2
The gas released on negative carbon electrode when current passes through acidified water?
  • A
    Carbon monoxide
  • B
    Sulpher dioxide
  • C
    Oxygen gas
  • D
    Hydrogen gas
    Correct
3
Which of the following is used for electroplating
  • A
    Chromium metal
    Correct
  • B
    Iron metal
  • C
    Aluminium metal
  • D
    Silver metal
4
The chemical effect produced by an electric current depends on
  • A
    Time of current passing
  • B
    Electrode
  • C
    Conducting solution
    Correct
  • D
    Nature of electrode
5
Which metal is electroplated on iron for making
  • A
    Copper metal
  • B
    Silver metal
  • C
    Tin metal
    Correct
  • D
    Chromium metal
6
In the process of refining copper metal a thin plate of pure copper is connected to
  • A
    Anode end
  • B
    Cathode end
    Correct
  • C
    Any of the above
  • D
    Electrolyte
7
During purification of copper, the electrolyte used is
  • A
    Iron sulphate
  • B
    Copper sulphate
    Correct
  • C
    Copper chloride
  • D
    Sodium chloride
8
When the free ends of tester are dipped into a solution, the magnetic needle shows deflection due to
  • A
    Flows of current
    Correct
  • B
    Magnetic effect
  • C
    Lighting effect
  • D
    Heating effect
9
While checking your tester, do not join its free ends for more than a few seconds otherwise
  • A
    Conductors get heated
  • B
    Bulb of the tester get fused
  • C
    Cells of the battery heat faster
  • D
    Cells of battery drain very quickly
    Correct
10
Lemon juice is good conductor of electricity due to
  • A
    Presence of citric acid
    Correct
  • B
    Presence of common salt
  • C
    Presence of free electron
  • D
    Absence of electron drawing agent
11
When minerals acids are added to water it produce ____________ to make it good conductor.
  • A
    Hydrocarbon ions
  • B
    Salts
  • C
    Hydrogen ions
    Correct
  • D
    Nitrogen oxide
12
We should not use electric supply from mains or generator to experiment because
  • A
    Energy is not sufficient
  • B
    May cause electric shocks
    Correct
  • C
    Flow of current can not be measured
  • D
    High voltage is not suitable
13
Close the continuous path of electric current is called
  • A
    Electric circuit
    Correct
  • B
    Good conductor
  • C
    Resistance
  • D
    Super conductor
14
Distilled water bad conductor of electricity but vinegar is good conductor as it contain
  • A
    Acetic acid
    Correct
  • B
    Oxalic acid
  • C
    Tartaric acid
  • D
    Sulphuric acid
15
The water from taps, hand pumps, wells and ponds is good conductor of electricity because of
  • A
    Small amount of dissolved salts
    Correct
  • B
    Small amount of acid
  • C
    All of these
  • D
    Small amount of base