Chemical Effects and Electric Currents Class 8
Q 1 – Which of the following is a bad conductor of electricity?
(a) Distilled water
(b) Silver nitrate
(c) Sulphuric acid
(d) Copper sulphate
Q 2 – Which of the following does not conduct electricity?
(a) Sugar solution
(b) Vinegar solution
(c) Lemon juice solution
(d) Caustic soda solution
Q 3 – An electric current can produce
(a) heating effect
(b) chemical effect
(c) magnetic effect
(d) all of these
Q 4 – Pure or distilled water is a
(a) poor conductor
(b) good conductor
(c) both (a) and (b)
(d) none of these
Chemical Effects and Electric Currents Class 8
Q 5 – Which of the following is a good conductor?
(a) Brick
(b) Steel
(c) Plastic
(d) Cotton
Q 6 – Polythene is
(a) a conductor
(b) an insulator
(c) both (a) and (b)
(d) none of these
Q 7 – Electroplating is based on
(a) heating effect of electricity
(b) chemical effect of electricity
(c) physical effect of electricity
(d) magnetic effect of electricity
Q 8 – Copper is
(a) good conductor
(b) an insulator
(c) both (a) and (b)
(d) none of these
Q 9 – Waste from an electroplating factory must be disposed off
(a) in the nearby river
(b) in the nearby pond
(c) in the nearby cornfield
(d) according to the disposal guidelines of Waste Management Bodies
Q 10 – An electrolyte is
(a) a metal
(b) a liquid that conducts current
(c) a non-metal
(d) none of these
Q 11 – Flow of electron is called
(a) electrolyte
(b) electroplating
(c) electrodes
(d) electric current
Q 12 – Which is not a non-electrolyte?
(a) Ethyl alcohol
(b) Sodium chloride
(c) Urea
(d) Sodium solution
Q 13 – An electric lamp glows due to
(a) heating effect
(b) magnetic effect
(c) chemical effect
(d) physical effect
Q 14 – Electroplating prevents
(a) corrosion
(b) passing of current
(c) dissociation
(d) shining
Q 15 – Which of the following is not used for electroplating metal articles?
(a) Nickel
(b) Silver
(c) Chromium
(d) Sodium
Q 16 – Iron objects can be protected by electroplating them with
(a) chromium
(b) nickel
(c) zinc
(d) all of these
Q 17 – In LEDs, the longer lead (wire) is always connected to the _______ terminal
(a) negative
(b) neutral
(c) positive
(d) Any terminal
Q 18 – The positive charged ions are called:
(a) cations
(b) anions
(c) ions
(d) none of these
Q 19 – When electrodes are immersed in water and electricity passed, the bubbles formed on the positive terminal is actually _______ gas.
(a) Hydrogen
(b) Carbon dioxide
(c) Oxygen
(d) Nitrogen
Q 21 – Why do we add little dilute sulphuric acid to copper sulphate solution during electroplating?
(a) To increase acidity
(b) To increase conductivity
(c) So that the colour becomes more prominent
(d) To burn copper sulphate
Q 22 – A coating of _________is deposited on iron to protect it from corrosion and formation of rust
(a) copper
(b) aluminium
(c) Zinc
(d) silver
Q 23 – Chromium plating is done on many objects such as car parts, bath taps, kitchen gas stove etc. Why?
(a) It does not corrode but prevents scratches
(b) It looks beautiful
(c) It costs less
(d) Articles can be sold at higher price
Q 24 – The process of depositing a layer of any desired metal on another material by means of electricity is called ___________.
(a) Electric plating
(b) Electroplating
(c) Electric depositing
(d) None of the above
Q 25 – Some liquids are good conductors of electricity and some are poor conductors. Which one is a poor conductor?
(a) Acidic solution
(b) Alkaline solution
(c) Common Salt solution
(d) Distilled water
Q 26 – Tin cans, used for storing food, are made by electroplating tin on iron. Why?
(a) Tin gives a shiny appearance
(b) To make the vessel cheap
(c) Tin is less reactive than iron.
(d) To make the vessel lighter
Q 27 – The negatively charged ions are called:
(a) cations
(b) anions
(c) ions
(d) none of these
Q 28 – Kerosene is:
(a) electrolyte
(b) non-electrolyte
(c) electrode
(d) none of these
Q 29 – Magnetic compass connected in a circuit is used to check:
(a) magnetism in electric current
(b) slow current
(c) small current
(d) none of these
Q 30 – LED glows:
(a) when a strong electric current flows through it
(b) whenever a weak electric current flows through it
(c) when no electric current flows through it
(d) none of these
Q 31 – Which of the following is a good conductor of electricity:
(a) Distilled water
(b) tap water
(c) kerosene
(d) none of these
Q 32 – When current flows through a conducting solution then the electrode connected to the
negative terminal of the battery is called :
(a) anode
(b) cathode
(c) rod
(d) none of these
Q 33 – Current is the flow of:
(a) electrons
(b) protons
(c) neutrons
(d) none of these
Q 34 – A battery is used to:
(a) convert chemical current into electricity
(b) maintain a potential difference current
(c) measure the current
(d) measure the temperature
Q 35 – When an electric current is passed through the copper sulphate solution, copper sulphate
dissociates into:
(a) copper and sulphur
(b) copper and oxygen
(c) copper and sulphate
(d) none of these
Q 36 – Adding lime water to tap water makes it:
(a) an electrolyte
(b) electrolysis
(c) no change occur
(d) none of these
Q 37 – ……………….. is deposited on Iron used in bridges and automobiles to protect it from
corrosion and formation of rust.
(a) Chromium
(b) Zinc
(c) lin
(d) None of these
Q 38 – Car parts, bath taps, kitchen gas burners, bicycle handlebars arc electroplated with:
(a) chromium
(b) zinc
(c) tin
(d) none of these
Q 39 – A tester is used to check the conduction of electricity through two liquids, labelled A and B. It is found that the bulb of the tester glows brightly for liquid. A white it glows very dimly
for liquid H. You would conclude that:
(a) liquid A is a better conductor than liquid B
(b) liquid B is a better conductor than liquid A
(c) both liquids are equally conducting
(d) conducting properties of liquid cannot be compared in this manner
Q 40 – Which one is the conductor
(a) brass
(b) plastic
(c) mica
(d) leather
Q 41 – The process in which a chemical change takes place in a substance when electric current is passed through it is called:
(a) electrolysis
(b) electrodes
(c) thermal conduction
(d) none of these
Q 42 – Electroplating is a process which is:
(a) magnetic effect of electricity
(b) heating effect of electricity
(c) chemical effect of electricity
(d) none of these
Q 43 – Which of the following liquid is poor conductor:
(a) salty water
(b) orange juice
(c) lemon juice
(d) none of these
Q 44 – The substance which is conductor of electricity is:
(a) rubber
(b) paper
(c) nails
(d) plastic
Q 45 – We use magnetic needle to find the effect of:
(a) slow electric current
(b) small electric current
(c) magnetism
(d) none of these
Q 46 – If a switch has some sparking, we will switch it off with the help of:
(a) an iron nail
(b) cotton cloth
(c) wooden stick
(d) anyone out of (b) and (c)
Q 47 – During electroplating in CuSO4, (Copper sulphate) solution …………………. will get deposit on electrode at negative terminal.
(a) Copper from positive electrode
(b) Sulphur
(c) Copper from CuSO4, solution
(d) None of these
Q 48 – Electroplating is a method of:
(a) making plates
(b) coating metal on another metal using electric current
(c) making plates which use electricity
(d) making metal with another metal
Q 49 – Which one of the following is the insulator:
(a) human body
(b) paper
(c) acid
(d) steel
Q 50 – Which liquid do not conduct electricity?
(a) common salt solution
(b) acidic solution
(c) distilled water
(d) none of these
Q 51 – An electrolyte is:
(a) a metal
(b) a solution
(c) a liquid that conducts electricity
(d) none of these
Class 8 Science Chemical Effects and Electric Currents Important Questions