Daily Practice Problems
Class 8 Science
Chemical Effects of Electric Current
daily practice problem

Question 1.

What are the good conductors of electricity?


Question 2.

How do you define the poor conductors of electricity?


Question 3.

Give three examples of good conductors of electricity.


Question 4.

Give three examples of poor conductors of electricity.


Question 5.

The salt solution is a ____________ of electricity.

(a) good conductor

(b) bad conductor

(c) insulator

(d) none of the above


Question 6.

Which of the following are good conductors of electricity?

(a) Hand pump’s water

(b) Well’s water

(c) Tap’s water

(d) All of the above


Question 7.

Most liquids that conduct electricity are solutions of _______, ________ and _____________.


Question 8.

The passage of an electric current through a conducting liquid causes _____________ reactions.

(a) physical

(b) chemical

(c) mathematical

(d) none of the above


Question 9.

What do you understand by the chemical effects of currents?


Question 10.

Define electroplating.


Question 11.

A coating of _______ is deposited on iron to protect it from corrosion and formation of rust.


Question 12.

Why tin cans are used for protecting food?

Question 13.

How electroplating is a useful process?


Question 14.

When salt is dissolved in distilled water, we obtain ________ solution.

(a) sugar

(b) salt

(c) juice

(d) light


Question 15.

When electric current is passed through the copper sulphate solution, copper sulphate dissociates into ___________ and ____________.

(a) oxygen, sulphate

(b) copper, nitrogen

(c) oxygen, nitrogen

(d) copper, sulphate


Question 16.

_______________ is the most common application of chemical effects of electric current.

(a) Electroplating

(b) Corrosion

(c) Rusting

(d) None of the above


Question 17.

Chromium plating can be done on:

(a) car parts

(b) bath taps

(c) gas burners

(d) all of the above


Question 18.

Chromium has a __________ appearance.

(a) dull

(b) shiny

(c) bright

(d) both (b) and (c)


Question 19.

Jewellery makers electroplate silver and gold on _________ expensive metals.

(a) less

(b) more

(c) very much

(d) none of the above


Question 20.

Iron tends to ________ and _________.

(a) shiny, brighter

(b) lovely, beautiful

(c) corrode, rust

(d) bad, worst