Class 8 Chemical Effects of current
Class 8 Science Home Page
Multiple Choice Questions (MCQs)
- Which of the following is an insulator?
(a) Human body
(b) Graphite
(c) Pure water
(d) Copper
- In electroplating, the object to be electroplated is made:
(a) anode
(b) cathode
(c) none
(d) both
- The extraction of metals from their ores by electrolysis is called:
(a) electroplating
(b) electrometallurgy
(c) electrorefining
(d) none
- The refining or purification of metals by passing electric current is called:
(a) electroplating
(b) electrolysis
(c) electrorefining
(d) none
- Carbon rods, used as electrodes are made up of:
(a) graphite
(b) wood
(b) iron
(d) diamond
- Which of these are the applications of electrolysis?
(a) Metal Extraction
(b) Electroplating
(c) Electrorefining
(d) All these
- In an electrolytic cell, the electrode which is connected to the positive terminal of the battery is called:
(a) cation
(b) anion
(c) cathode
(d) anode
- Which of these is plated on the iron to prevent it from chemically reacting with food?
(a) Gold
(b) Silver
(c) Chromium
(d) Tin
- Out of the following, which metal is used to electroplate iron to make it shining and rust resistant?
(a) Chromium
(b) Gold
(c) Zinc
(d) Copper
Fill in the blanks:
- Electroplating is based on the —chemical—-effect of electric current.
- Wood is a—bad— conductor of electricity.
- Pencil lead is a.
- The flow of electrons is called—current—.
- Tap water is a—good conductor of electricity.
- Tap water conducts electricity because it has dissolved in it.
- The process used to purify a metal is called —-electroplating.
State whether ‘True’ (T) or ‘False’ (F):
- Chromium corrodes easily. F
- The sugar solution is an electrolyte. F
- Cations are negatively charged particles. T
- Electrolytes produce ions when dissolved in water. T
- A cycle rim is made of iron that is electroplated with chromium. T
- Touching an electrical appliance with wet hands can be very dangerous. T
Class 8 Science Home Page