Chemistry For Class IX (New Book ) - Chapter No. 7 - Electrochemistry - Multiple Choice Questions And Fill In The Blanks

GO TO INDEX

Chapter No.7 - Electrochemistry
MCQs And Fill In The Blanks
Text Book Exercise

SECTION- A: MULTIPLE CHOICE QUESTIONS
Tick Mark (✓) the correct answer

1. Alloy of Cu - Sn is called
(a) Brass
(b) Bronze
(c) Monel
(d) Bell metal ✓

2. Which one is Alloy.
(a) Graphite
(b) Mercury
(c) Steel ✓
(d) Water

3. Value of 1 Faraday is equal to:
(a) 9.65 C
(b) 9650 C
(c) 96500 C ✓
(d) 965 C

4. Which one is non electrolyte.
(a) Aqueous HCl
(b) Aqueous NaCl
(c) Molten KCl
(d) Urea ✓

5. Which one is oxidizing agent.
(a) Al
(b) H₂S
(c) Cl₂ ✓
(d) NaH

6. Which one is reducing agent.
(a) H₂S0₄
(b) HNO₃
(c) Al ✓
(d) I₂

7. Which one forms weak electrolyte solution with water:
(a) HCl
(b) KOH
(c) NaCl
(d) CH₃COOH ✓

8. In Daniel cell ____ is used as cathode.
(a) Zn
(b) Cu ✓
(c) Sn
(d) Pb

9. 1 g equivalent weight of Al is equal to:
(a) 9 g ✓
(b) 27 g
(c) 54 g
(d) 1 g

10. Which one is correct statement.
(a) Oxidation occurs at cathode.
(b) Reduction occurs at anode
(c) Reduction occurs at cathode ✓
(d) Ions lose electrons at cathode.

11. Electrochemistry deals with the conversion of:
(a) electrical energy into chemical energy
(b) chemical energy into electrical energy
(c) Both of 'a' and 'b' ✓
(d) None of them

12. From a chemical substance, oxidation may involve:
(a) introduction of oxygen
(b) removal of hydrogen
(c) Both 'a' & 'b' ✓
(d) None of these

13. From a chemical substance, reduction may involve:
(a) removal of oxygen
(b) addition of oxygen
(c) removal of hydrogen
(d) All of them ✓

14. The electrochemical reaction in which atom, molecule or ion loses electrons is called:
(a) reduction reaction
(b) oxidation reaction ✓
(c) electrolytic reaction
(d) cathodic reaction

15. In oxidation reaction, oxidation number:
(a) becomes zero
(b) remains the same
(c) decreases
(d) increases ✓

16. The electrochemical reaction in which atom, molecule or ion accepts electron is called:
(a) reduction reaction ✓
(b) oxidation reaction
(c) electrolytic reaction
(d) cathodic reaction

17. In reduction reaction, oxidation number:
(a) becomes zero
(b) remains the same
(c) decreases ✓
(d) increases

18. Which one of these is a reducing agent?
(a) Cl₂
(b) KMnO₄
(c) H₂SO₄
(d) Zn ✓

19. Which one of these is NOT a reducing agent?
(a) Zn
(b) HNO₃ ✓
(c) Al
(d) KH

20. The reaction occurs at each electrode is called:
(a) zero cell reaction
(b) quarter cell reaction
(c) half cell reaction ✓
(d) full cell reaction

21. Types of electrochemical cells are:
(a) two ✓
(b) three
(c) four
(d) five

22. Which of the following is a strong electrolyte?
(a) H₂CO₃
(b) NH₄OH (c) AgCl
(d) NaCl ✓

23. Which of the following is NOT an electrolyte?
(a) Benzene
(b) Glucose
(c) Both of 'a' & 'b' ✓
(d) None of these

24. The substance used for electrolysis is called:
(a) electrolyte ✓
(b) cell
(c) electricity
(d) None of them

25. The device that converts chemical energy into electrical energy or electrical energy into chemical energy is called:
(a) electrochemical cell ✓
(c) photocell
(b) electrolytic cell
(d) pencil cell

26. In which type of cells, oxidation (loss of electrons) occurs at anode and reduction (gain of electrons) occurs at the cathode?
(a) Electrochemical
(b) Electrolytic ✓
(c) Primary
(d) Secondary

27. Faraday's First Law of Electrolysis states that the amount of any substance that is deposited or liberated at an electrode during electrolysis is directly proportional to the:
(a) charge deposited on electrodes
(b) mass of the substance or electrolyte
(c) their chemical equivalent masses
(d) quantity of electricity passed through the electrolyte ✓

28. Coulomb (C) = ____:
(a) Ampere (A) + time (t)
(b) Ampere (A) - time (t)
(c) Ampere (A) x time (t) ✓
(d) Ampere (A) ÷ time (t)

29. The mass of the substance liberated or deposited per unit charge that passes is called:
(a) electrochemical equivalent ✓
(b) mass equivalent
(c) physio-chemical equivalent
(d) volume equivalent

30. Equivalent mass = ____:
(a) Atomic mass x Valency
(b) Atomic mass / Valency ✓
(c) Atomic mass + Valency
(d) Atomic mass x (Valency)²

31. According to Faraday's Second Law of Electrolysis, the amount of different substances deposited or liberated due to passage of the same quantity of current through different electrolysis are proportional to:
(a) charge deposited on electrodes
(b) mass of the substance or electrolyte
(c) their chemical equivalent masses ✓
(d) quantity of electricity passed through the electrolyte

32. Quantity of charge which deposits or liberates 1 gm equivalent weight of a substance is called:
(a) 1 Farad
(b) 1 Ampere
(c) 1 Coulomb
(d) 1 Faraday ✓

33. Dry cell is also called:
(a) Leclanche cell ✓
(b) secondary battery
(c) lead storage battery
(d) None of these

34. Dry cell uses:
(a) manganese dioxide as anode & zinc as cathode
(b) zinc as anode & manganese dioxide as cathode ✓
(c) lead as anode & lead oxide as cathode
(d) lead oxide as anode & lead as cathode

35. In a dry cell, this is used as an electrolyte.
(a) NH₄Cl paste
(b) ZnCl₂ paste
(c) either 'a' or 'b' ✓
(d) Both 'a' & 'b'

36. Lead storage battery is an example of:
(a) Leclanche cell
(b) secondary battery ✓
(c) primary battery
(d) None of them

37. Lead storage battery uses:
(a) manganese dioxide as anode & zinc as cathode
(b) zinc as anode & manganese dioxide as cathode
(c) lead as anode & lead oxide as cathode ✓
(d) lead oxide as anode & lead as cathode

38. In lead storage battery, this is used as electrolyte.
(a) NH₄Cl paste
(b) ZnCl₂ paste
(c) solution of H₂SO₄ ✓
(d) None of these

39. Number of alloys, used for different purposes, are:
(a) 70
(b) 700
(c) 7000 ✓
(d) 70000

40. Brass is an alloy of:
(a) Cu-Zn ✓
(b) Cu-Sn
(c) Cu-Zn-Sn
(d) Ag-Cu

41. Alloy of iron and carbon is called:
(a) Brass
(b) Bronze
(c) Duralumin
(d) Steel ✓

42. It is called 100% pure gold.
(a) 24 karat ✓
(b) 22 karat
(c) 18 karat
(d) 10 karat

43. To make stainless steel, iron is mixed with:
(a) Cu Zn
(b) Cu-Sn
(c) Cr-Ni ✓
(d) Ag-Cu

44. The coating of metal at the surface of other metal by the electrolytic process is called:
(a) electrolysis
(b) electrolyte
(c) galvanizing
(d) electroplating ✓

45. The process in which zinc is electrolytically coated at the surface of other base metal is called:
(a) electrolysis
(b) electrolyte
(c) galvanizing ✓
(d) electroplating

46. In W = ZAt, 'Z' is called:
(a) constant
(b) product
(c) electrochemical equivalent ✓
(d) None of them

FILL IN THE BLANKS:

1. Oxidation is the loss of electron by chemical substance.
2. Reduction is the gain of electron by chemical substance.
3. An electrolyte consists of free moving ions and conduct electricity.
4. An electrode is an electrical conductor.
5. The electrode at which oxidation occurs is called anode.
6. The electrode at which reduction occurs is called cathode.
7. Electrolysis is a process of migration of ions towards cathode and anode when current passes through en electrolyte.
8. Oxidizing agent helps in oxidation by accepting electrons.
9. Reducing agent helps in reduction by losing electrons.
10. A galvanic cell converts chemical energy into electrical energy.
11. An electrolytic cell uses electrical energy to derive a non spontaneous reaction.
12. Corrosion of iron is called rusting.
13. Corrosion of metal can be prevented by alloying, paint or electroplating metal by zinc, tin, silver, chromium etc.
14. An alloy is a mixture of metal with metal or metal with non metal.
15. Digital watches, calculators, cars and mobile phones. powered by batteries or dry cells.
16. 24 karat gold is called 100% pure gold.
17. The formula of rust is (iron (III) oxide) (Fe₂O₃.nH₂O)

CONCEPT MAP

Point To Remember:

Reaction: Oxidation reaction

• Status: Loss of Electron
• Electrode: Anode (positive electrode)
• Ion on Anode: Anion
• Agent: Reducing agent (Cation)

Reaction: Reduction reaction

• Status: Gain of Electron
• Electrode: Cathode (negative electrode)
• Ion on Cathode: Cation
• Agent: Oxidizing agent (Anion)

Some Important Alloys With Their Components And Applications

Name Of Alloy	Components	Applications
Bell Metal	Cu-Sn	Casting of bell
Brass	Cu-Zn	Door nobs and hand rails due to antibacterial nature, Hose nozzles, Stamping dies.
Bronze	Cu-Zn-Sn	Coins, medals, tools, etc.
Monel	Ni-Cu-Fe	Corrosion resistant containers
Duralumin	Al-Cu-Mg-Ni	Boat, Aircraft etc.
Solder	Sn-Pb-Cu-Sb	Joining electrical components into circuits
Alnico	Fe-Al-Ni-Co	Magnets used in loud speakers
Amalgam	Hg-Ag-Cu-Zn	Dental filling
Cupronickel	Cu-Ni-Mn	Coins
Pewter	Sn-Cu-Pb-Sb-Bi	Ornaments
Sterling silver	Ag-Cu	Cutlery set, Medical tools
White Gold (18 Karat)	Au-Pb-Ag-Cu	Jewelry
Red Gold (18 K)	Au-Cu	Jewelry
Yellow Gold (22 K)	Au-Ag-Cu-Zn	Jewelry

Elements Use In Alloys with Their Symbols:

• Ag = Silver (Argentum)
• Al = Aluminium
• Au = Gold (Aurum)
• Bi = Bismuth
• Co = Cobalt
• Cu = Copper
• Fe = Iron (Ferrum)
• Hg = Mercury (Hydragyrum)
• Mg = Magnesium
• Mn = Manganese
• Ni = Nickel
• Pb = Lead (Plumbum)
• Sb = Antimony (Stibium)
• Sn = Tin (Stannum)
• Zn = Zinc