Question 1

Which of the following liquids is a good conductor of electricity?

Accepted Answer

Salt water is a good conductor of electricity because it contains dissolved salts which dissociate into ions, allowing electric current to flow through the solution easily. Distilled water, honey, and cooking oil lack free ions and are poor conductors.

Question 2

The process of depositing a layer of any desired metal on another material by means of electricity is called:

Accepted Answer

Electroplating is the process of depositing a layer of any desired metal on another material by means of electricity. It is widely used for coating objects with a thin layer of superior metal for corrosion resistance or decorative purposes.

Question 3

An electric current passing through a conducting solution causes:

Accepted Answer

An electric current passing through a conducting solution causes chemical effects. These effects can include the formation of gas bubbles, deposition of metal on electrodes, or change in color of the solution.

Question 4

Which of the following metals is electroplated on iron to prevent corrosion and give a shiny appearance?

Accepted Answer

Chromium is electroplated on objects like car parts, bath taps, and kitchen gas burners because it does not corrode and has a shiny appearance, although it is expensive and not made entirely of chromium.

Question 5

When electric current is passed through acidified water, gases released at the positive and negative electrodes are respectively:

Accepted Answer

When electric current passes through water, water molecules split into oxygen and hydrogen. Oxygen gas is released at the positive electrode (anode) and hydrogen gas is released at the negative electrode (cathode).

Chemical Effects of Electric Current — NCERT Class 8 Science Important Questions & Revision Notes