Chemical Effects of Electric Current Practice Questions

Class 8 · Science · 1148 free MCQs with instant results and detailed explanations.

1148
Total
366
Easy
554
Medium
228
Hard

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Topics in Chemical Effects of Electric Current

Chemical Effects 374
Conductors of Liquids 378
Electroplating 396

Sample Questions from Chemical Effects of Electric Current

Here are 10 sample questions. Start a quiz to get randomized questions with scoring.

Q1
Easy
Which of the following is a good conductor of electricity when dissolved in water?
A. Table salt (NaCl)
B. Sugar (C12H22O11)
C. Cooking oil
D. Sand
Show Answer & Explanation
Correct Answer: A
Table salt (NaCl) dissociates into ions in water, allowing it to conduct electricity effectively. In contrast, sugar, cooking oil, and sand do not produce ions that facilitate electrical conductivity.
Q2
Easy
Which of the following is an example of a liquid conductor?
A. Saltwater
B. Pure water
C. Oil
D. Mercury
Show Answer & Explanation
Correct Answer: A
Saltwater conducts electricity due to the presence of ions, while pure water does not.
Q3
Easy
What happens to the flow of electricity in a liquid conductor?
A. It increases resistance
B. It decreases resistance
C. It stops
D. It changes direction
Show Answer & Explanation
Correct Answer: B
In a liquid conductor, the flow of electricity can decrease resistance due to free-moving ions.
Q4
Medium
Which of the following liquids is a good conductor of electricity?
A. Distilled water
B. Saltwater
C. Sugar syrup
D. Vegetable oil
Show Answer & Explanation
Correct Answer: B
Saltwater contains ions that can carry electric current, making it a good conductor.
Q5
Medium
What happens when an electric current passes through acidulated water?
A. It freezes
B. Gas bubbles form
C. It changes color
D. No change occurs
Show Answer & Explanation
Correct Answer: B
Acidulated water decomposes into hydrogen and oxygen gases when current passes through it, leading to gas bubbles.
Q6
Medium
Which factor does NOT affect the conductivity of a liquid?
A. Temperature
B. Concentration of ions
C. Type of liquid
D. Color of the liquid
Show Answer & Explanation
Correct Answer: D
The color of the liquid does not influence its ability to conduct electricity; itโ€™s the ions and their concentration that matter.
Q7
Medium
Why is pure water considered a poor conductor of electricity?
A. It lacks ions
B. It is too cold
C. It is too dense
D. It evaporates quickly
Show Answer & Explanation
Correct Answer: A
Pure water does not contain sufficient ions to carry an electric current, making it a poor conductor.
Q8
Hard
Which of the following liquids is a good conductor of electricity?
A. Distilled water
B. Saltwater
C. Sugar solution
D. Vegetable oil
Show Answer & Explanation
Correct Answer: B
Saltwater contains ions which facilitate electric current flow, while distilled water, sugar solutions, and vegetable oil do not.
Q9
Hard
What happens to the conductivity of a salt solution when more salt is added?
A. Decreases
B. Increases
C. Remains the same
D. Becomes unpredictable
Show Answer & Explanation
Correct Answer: B
Adding more salt increases the number of ions in the solution, thereby enhancing its conductivity.
Q10
Hard
Which of the following statements is NOT true regarding conductors of electricity?
A. Metals conduct electricity by the flow of electrons.
B. Pure water is a good conductor of electricity.
C. Electrolytes conduct electricity through ion movement.
D. Some liquids require a solute to conduct electricity.
Show Answer & Explanation
Correct Answer: B
Pure water lacks sufficient ions to conduct electricity effectively, unlike saltwater or acidic solutions.

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Chemical Effects of Electric Current โ€” Class 8 Science Practice Questions Online

This page contains 1148 practice MCQs for the chapter Chemical Effects of Electric Current in Class 8 Science. The questions are organized by difficulty โ€” 366 easy, 554 medium, 228 hard โ€” so you can choose the right level for your preparation.

Every question includes a detailed explanation to help you understand the concept, not just memorize answers. Take a timed quiz to simulate exam conditions, or practice at your own pace with no time limit. This chapter covers 3 topics, giving you comprehensive coverage of the entire chapter.