Education For All Entry Test Entry Test Preparation 2015, Chemistry BOOK 1 Chapter # 10 ELECTROCHEMISTRY, MCQS with Answer Keys

Entry Test Preparation 2015, Chemistry BOOK 1 Chapter # 10 ELECTROCHEMISTRY, MCQS with Answer Keys

zohaib hassan 10:48 PM Entry Test

Entry Test Preparation 2015

ChemistryChapter # 10
ELECTROCHEMISTRY

Direction

You are given following questions from the topic, with four choices A through D. Select the choice that will answer the question best.

1. A solution of sodium sulphate was electrolysed using some inert electrodes. The products at the electrodes are

A. O₂, H₂ B. O₂, Na

C. O₂, SO₂ D. O₂, S2O₈^2-

2. Coinage metals are reactive:

A. least B. most

C. moderate D. none of these

3. Out of Cu, Ag, Fe and Zn the metal which can displace all other from their salt solutions is

A. Ag B. Cu

C. Zn D. Fe

4. The conductivity of strong electrolyte

A. Increases on dilution slightly

B. Does not change on dilution

C. Decreases on dilution

D. Depends on density of electrolyte it self

5. For 12 V in lead accumulator ____cells are connected.

A. 2 B. 6

C. 9 D. 2

6. Which of the following is the use of electrolysis?

A. Extraction of metals B. Electroplating

C. Both A and B D. None of the above

7. Which is the strongest reducing agent:

A. Zn_(s)B. Cr_(s)

C. H_2(g)D. Fe³⁺_(aq)

8. Cr is placed above hydrogen in electrochemical series it has_____ reduction potential than hydrogen.

A. higher B. lower

C. equel D. none

9. Which is the strong oxidizing agent in F2,Cl2,Br2

A. F2 B. Cl2

C. Br2 D. all are equal

10. In fuel cell ____react in presence of KOH.

A. ZnO,MnO2 B. CuSO₄, KCl

C. HgCl₂ D. H_2,O₂

11. Standard reduction electrode potential of three metals A, B and C are erespectively +0.05 V, -3.0V and -1.2V. The reducing power of

A. B > C > A B. A > B > C

C. C > B > A D. A > C > B

12. Conductivity is due to flow of electrons in:

A. Ionic solids B. Covalent solids

C. Metallic solids D. Molecular solids

13. If the salt bridge is not used between two half cells then voltage

A. decreases rapidly B. decreases slowly

C. does not change D. drops to zero

14. Fuel cell is used in

A. B. 550 cm³

C. 5.6 cm³ D. 11.2 cm³

15. Which of the following is non rechargeable battery

A. NICAD B. Alkaline battery

C. Fuel cell D. none

16. Using inert electrodes like Pt or graphite the electrolysis of aqueous sodium chloride produces at chatode

A. Cl₂ gas B. H₂ gas

C. O₂ gas D. HCl gas

17. In the presence of copper electrodes the electrolysis of aqueous CuSO₄ produces at cathode

A. H₂ gas B. O₂ gas

C. SO₂ gas D. Cu metal

18. The cathodic reaction in the electrolysis of dil. H₂SO₄ with Pt electrodes

A. reduction

B. oxidation

C. both oxidation and reduction

D. neither oxidation or reduction

19. Passage of electric current through the metals is due to

A. oxidation reaction B. reduction reaction

C. electrolysis D. free movement of electrons

20. In the electrolysis of aqueous solution of sodium nitrate, the ions which are reduced at the cathode are

A. H₃O⁺ B. Na⁺

C. OH^- D. NO^3-

21. A standard hydrogen electrode is used as standard electrode of which electrode potential is arbitrarily taken as

A. +1 B. -1

C. 0.1 D. zero

22. The reduction potential of copper electrode is +0.34 V and that of Zn electrode is -0.76 V. When these two are coupled the e.m.f. of the cell is

A. -0.42 V B. +0.42

C. -1.10 V D. +1.10 V

23. A dry alkaline cell has porous Zn anode and MnO2 as cathode the electrolyte used is

A. Ca(OH)₂ B. NaOH

C. KOH D. NH₄OH

24. In electronic watches or electronic calculator the tiny batteries used are

A. Alkaline battery B. NICAD battery

C. Fuel cell D. Silver oxide battery

25. Silver oxide battery has a voltage of

A. 2.0 V B. 1.5 V

C. 2.5 V D. 1.0 V

26. Which statement is incorrect for NICAD battery

A. The electrolyte is alkali B. Cd acts as anode

C. MnO₂ acts as electrolyte D. NiO₂ acts as cathode

27. The oxidation number of H is – 1 in the compound

A. H₂O B. H₃BO₃

C. NaOH D. NaH

28. In F₂O the oxidation state of oxygen is

A. -2 B. -1

C. +1 D. +2

29. The oxidation number of Mn in KMnO₄ is

A. +2 B. +4

C. +6 D. +7

30. The oxidation state of Cr in K₂Cr₂O₇ is

A. +3 B. +6

C. +9 D. +4

31. An oxidizing agent in a chemical reaction is the substance which

A. loses electrons B. gains electrons

C. pH is changed D. acts as a catalyst

32. In the reaction

Cu + HNO₃

Cu(NO₃)₂ + NO + H₂O the atom which is oxidized

A. Cu B. H

C. N D. O

33. In KO₂the oxidation state of oxygen is

A. -2 B. -1

C. +1/2 D. -1/2

34. Standard reduction potential of F is the highest in the electrochemical series which is

A. +4.87 B. +3.87

C. +2.87 D. +1.87

35. Fe can displace Cu form CuSO₄ solution

A. Fe is ferromagnetic

B. Fe is below Cu in electrochemical series

C. Fe is above Cu in electrochemical series

D. Fe exist in divalent oxidation sate

36. Which of the following reaction does not involve either oxidation or reduction?

A. VO^-2

V₂O₃ B. Na

Na⁺

C. CrO₄^-2

Cr₂O₇^-2 D. Zn^-2

Zn

37. In the reaction, MnO₄^- + 5Fe²⁺ + 8H⁺

Mn²⁺ + 5Fe³⁺ + 4H₂O, the oxidation

number of Manganese:

A. increases from – 1 to +2 B. decreases from +7 to +2

C. increases from +3 to +5 D. remains unchanged

38. The potential difference responsible for the flow of current from the electrode of higher potential to one of lower potential is called:

A. electrolysis B. electromotive force

C. resistance D. electrolytic conduction

39. “The current strength flowing through a conductor at uniform temperature is proportional to the potential difference at the end of the conductor and is inversely proportional to the resistance”. This is the statement of:

A. Faraday law B. Law of themodynamics

C. Ohm’s law D. Raoult’s law

40. In a cell containing Zinc electrode & normal hydrogen electrode, the Zinc electrode acts as:

A. Cathode B. Anode

C. Reducing electrode D. None of the above

41. The e.m.f. of Galvanic cell of the reaction is:

Zn

Zn^-2 + 2e^- (E^o = -0.76 V)

Cu⁺² + 2e

Cu (E^o = +0.34 V)

A. -0.42V B. -0.10

C. +1.10V D. +0.42V

42. The best conductor of electricity is 1M solution of:

A. CH₃COOH B. H₂SO₄

C. H₃PO₄ D. H₃BO₃

43. The equation, NaCl

Na + Cl represents:

A. Electrolysis B. Hydration

C. Theory of ionization D. Common ion effect

44. Which one of the following salts will hydrolyse in water to give basic solution

A. NaCl B. NH₄Cl

C. KCl D. Na₂SO₄

45. The standard reduction potential at 298K for the following half reaction are given against each?

Zn²⁺ + 2e^-

Zn_(s) ; -0.762v

Cr²⁺ + 2e^-

Cr_(s) ; -0.740v

2H⁺ + 2e^-

H2_(g) ; -0.000v

Fe³⁺_(aq) + 3e^-

Fe_(aq) ; -0.770v

46. The standard reduction potential for Fe²⁺ |Fe & Sn²⁺| Sn electrodes are -0.44v & 0.14V respectively. For the cell reaction:

Fe²⁺ +Sn

Fe + Sn²⁺

A. +0.30V B. -0.58V

C. +0.58V D. -0.30V

47. The most common oxidation state of an element is -2. The number of electrons in its outer most shell is:

A. 2 B. 4

C. 6 D. 8

48. The degree of dissociation of an electrolyte does not depends on:

A. nature of electrolyte B. dilution

C. catalytic action D. temperature

49. The degree of dissociation of an electrolyte increases as:

A. dilution increases B. dilution decreases

C. pressure decreases D. low degree of ionization

50. An indicator that changes colour from red to yellow in the presence of an alkaline solution is called:

A. Methyl orange B. Litmus paper

C. Phenolpthalein D. Methyl red

ANSWERS

(electrochemistry)

1	A	2	A	3	C
4	A	5	B	6	C
7	A	8	B	9	A
10	D	11	A	12	C
13	D	14	D	15	B
16	B	17	D	18	A
19	D	20	A	21	D
22	D	23	C	24	D
25	B	26	C	27	D
28	D	29	D	30	B
31	B	32	A	33	D
34	C	35	C	36	C
37	B	38	B	39	C
40	B	41	C	42	B
43	C	44	B	45	A
46	D	47	C	48	C
49	A	50	A

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