Question

MCQs on chemical effects on electric current

Answer 1

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 while it glows very dimly for liquid B. You would conclude that
(i) liquid A is a better conductor than liquid B.
(ii) liquid B is a better conductor than liquid A.
(iii) both liquids are equally conducting.
(iv) conducting properties of liquid cannot be compared in this manner.
Answer:
(i) Liquid A is a better conductor than liquid B.

Answer 2

Question 1.

Which of the following is a bad conductor of electricity?

(a) Distilled water

(b) Silver nitrate

(c) Sulphuric acid

(d) Copper sulphate

Question 2.

Which of the following does not conduct electricity?

(a) Sugar solution

(b) Vinegar solution

(c) Lemon juice solution

(d) Caustic soda solution

Question 3.

An electric current can produce

(a) heating effect

(b) chemical effect

(c) magnetic effect

(d) all of these

Question 4.

Pure or distilled water is a

(a) poor conductor

(b) good conductor

(c) both (a) and (b)

(d) none of these

Question 5.

Which of the following is a good conductor?

(a) Brick

(b) Steel

(c) Plastic

(d) Cotton

Question 6.

Polythene is

(a) a conductor

(b) an insulator

(c) both (a) and (b)

(d) none of these

Question 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

Question 8.

Copper is

(a) a good conductor

(b) an insulator

(c) both (a) and (b)

(d) none of these

Answer

Question 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

Answer

Question 10.

An electrolyte is

(a) a metal

(b) a liquid that conducts current

(c) a non-metal

(d) none of these

Answer

Question 11.

Flow of electron is called

(a) electrolyte

(b) electroplating

(c) electrodes

(d) electric current

Answer

Question 12.

Which is not a non-electrolyte?

(a) Ethyl alcohol

(b) Sodium chloride

(c) Urea

(d) Sodium solution

Answer

Question 13.

An electric lamp glows due to

(a) heating effect

(b) magnetic effect

(c) chemical effect

(d) physical effect

Answer

Question 14.

Electroplating prevents

(a) corrosion

(b) passing of current

(c) dissociation

(d) shining

Answer

Question 15.

Which of the following is not used for electroplating metal articles?

(a) Nickel

(b) Silver

(c) Chromium

(d) Sodium

Answer

Question 16.

Iron objects can be protected by electroplating them with

(a) chromium

(b) nickel

(c) zinc

(d) all of these

Answer

Question 17.

In LEDs, the longer lead (wire) is always connected to the _______ terminal

(a) negative

(b) neutral

(c) positive

(d) Any terminal

Answer

Question 18.

Tap water is a good conductor of electricity while distilled water is not because

(a) Tap water contain salts

(b) Distilled water do not contain salt

(c) Only (a) is correct

(d) Both (a) & (b) is correct

Answer

Question 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

Answer

Question 20.

When electrodes are immersed in water and electricity passed, the bubbles formed on the negative terminal is actually _______ gas.

(a) Hydrogen

(b) Carbon dioxide

(c) Oxygen

(d) Nitrogen

Answer

Question 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

Answer

Question 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

Answer

Question 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

Answer

Question 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

Question 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

Answer

Question 26.

Tin cans, used for storing food, are made by electroplating tin onto 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

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