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Wednesday, 11 November 2015

Chemical Effects of Electric Current - Multiple Choice Questions

Chemical Effects of Electric Current - Multiple Choice Questions Points : chemical effects of electric current, multiple choice questions and answers, electrical objective type question answers, mcqs 1. The relation among E.CE. (z) and chemical equal weight (E) is that _______.
(i) E/z is constant for au elements
(ii) E/z is different for different elements
(iii) E2/z Is constant for all elements
(iv) E/z2 is constant for all elements

2. Positively charged atom is at times called ______.
(i) donor atom
(ii) acceptor atom
(iii) cation
(iv) anion

3. Current conduction through solution of an electrolyte is by
(i) free electrons
(ii) ions
(iii) atoms
(iv) valence electrons

4. Out of following, EC.E. of ______ is largest.
(i) copper
(is) iron
(iii) nickel
(Iv) silver

5. For method of electrolysis, we need ______.
(i) d. C. supply
(ii) ac. supply
(iii) varying voltage
(iv) both d.c. and a.c. supply

6. Through electrolysis, mass of an element liberated at electrode is _______ of element.
(i) directly proportional to the valency
(ii) inversely proportional to atomic weight
(iii) directly proportional to chemical eq. wt
(iv) none of the above

7. Mass of an element deposit or liberated at an electrode through electrolysis is _____ the amount of electricity pass through electrolyte.
(i) directly proportional to
(ii) inversely proportional to
(iii) independent of
(Iv) none of the above

8. Existence of to positive plates of a lead-acid cell is about that of negative plates.
(i) the same as
(ii) half
(iii) twice
(iv) thrice

9. Major drawback of a primary cell is that
(i) chemical action is not reversible
(ii) chemical action is reversible
(iii) the electrolyte used is very costly
(iv) it Is not portable

10. The most usually use cell is ______.
(i) lead-acid cell
(ii) nickel-iron cell
(iii) nickel-cadmium cell
(iv) fuel cell

11. E.m.f. of a cell does not depend upon _____.
(i) nature of electrolyte
(ii) nature of material of electrodes
(iii) concentration of electrolyte
(iv) size and spacing of electrodes

12. Material of positive plates of a lead-acid cell is than those of negative plates.
(i) mechanically stronger
(ii) poorer in conductivity
(iii) better in conductivity
(iv) less chemically active

13. As similar amount of electricity is approved during silver and copper voltage meters in series, masses of silver (Ag) and copper (Cu) deposited on respective cathodes will be in the part of their ______.
(i) atomic weights
(ii) valency
(iii) chemical equivalent weights
(iv) none of the above

14. As a lead-acid cell is entirely charged
(i) anode is converted into Pb
(ii) cathode is converted into PbO2
(iii) specific gravity of H2SO2 rises to about 1.28
(iv) both plates become red

15. If two dissimilar elements in electro-chemical series are use as the electrodes in a cell, one higher in the series ______.
(i) will be positive plate
(ii) will be negative plate
(iii) can be positive or negative plate
(iv) none of the above

16. Efficiency of a primary cell is on ______.
(i) 25%
(ii) 15%
(iii) 70 %
(iv) 35 %

17. The marketable lead-acid cell has 15 plates. Number of negative plates will be _____.
(i) 7
(ii) 9
(iii) 10
(iv) 8

18. Nickel-iron batteries are use in ________.
(i) starting of car engine
(ii) hospitals as an emergency supply
(iii) submarines
(iv) railway train lighting system

19. Silver and zinc voltameters are joined in series. Current off amperes is approved through them for time t. If m gram of zinc is liberated, then the mass of silver deposit is almost
(i) m
(ii) 3.3m
(iii) 15 m
(iv) 23 m

20. Lead-acid cell has 13 plates. In absence of manufacturer’s data, charging current must be
(i) 13 A
(ii) 2 A
(iii) 6 A
(iv) 3 A

21. The ampere hour competence of a lead-acid cell is on _______.
(i) 25%
(ii) 50%
(iii) 75%
(iv) 90 %

22. In practice, state of discharge of a lead acid cell is resolute with _______.
(i) e.m.f. of the cell
(ii) specific gravity of the electrolyte
(iii) colour of plates of the cell
(iv) none of the above

23. State of charge of nickel-cadmium cell is resolute by
(i) e.m.f. of the cell
(ii) specific gravity of the elecolyte (KOH)
(iii) colour of plates
(iv) none of the above

24. A 3 resistor and a silver voltameter of resistance 2 are connected in sequence across a cell. How will rate of deposition of silver be effect if a resistance of 2 is connected in parallel by the voltameter?
(i) It will decrease by 25 %
(ii) It will increase by 25 %
(iii) It will increase by 125 %
(iv) It will decrease by 125 %

25. Internal resistance of a lead-acid cell is mostly due to
(i) positive plates
(ii) negative plates
(iii) both positive and negative plates
(iv) electrolyte

26. While 1 C of charge is allowable to flow through an elecytrolyte, mass of matter deposit is equivalent to
(i) E.C.E. of that substance
(ii) Equivalent weight of that substance
(iii) Atomic weight of that substance
(iv) none of the above

27 What is volume of hydrogen liberated at N.T.P. through a charge which liberates 0.3175 g of copper?
(i) 105 c.c.
(ii) 56 c.c.
(iii) 112 c.c.
(iv) 224 c.c.

28. In the over question, what percentage of energy supplied will be done in form of heat?
(i) 60%
(ii) 50%
(iii) 80%
(iv) 25 %

29. If exact gravity of electrolyte (H2SO) in a lead-acid cell increases, the inner resistance of cell _______.
(i) remains unchanged
(ii) is increased
(iii) is decreased
(iv) none of the above

30. A multiplate creation is use in a lead-acid cell to
(i) increase the capacity of the cell
(ii) increase the emf of the cell
(iii) increase the internal resistance of the cell
(iv) facilitate cell connections

31. Exact gravity of electrolyte (H2SO4,) of a lead-acid cell is on 1.25 The cell is about
(i) 25 % charged
(ii) 50 % charged
(iii) 75% charged
(iv) 100 % charged

32. A charge q liberated n moles of oxygen. Number of moles of hydrogen liberate through the similar charge is
(i) n
(ii) n/2
(iii) 2n
(iv) 4n

33. The condition of charge of a nickel-iron cell is resolute through
(i) the specific gravity of electrolyte (KOH)
(ii) e.m.f. of the cell
(iii) colour of plates
(iv) none of the above

34. How a lot electricity must be passed through an electrolyte solution for one second so that one grain equal of the substance is liberated at electrode?
(i) 965C
(ii) 400C
(iii) 96500C
(iv) 550C

35. The chief difficulty of a nickel-cadmium cell is that it
(i) takes a long time for charging
(ii) has high internal resistance
(iii) has a short life
(iv) is very expensive

36. Series battery of 12 lead acid accumulators, every of e.m.f. 2 V and internal resistance 1/24 Ω, is to be charged as of 240 V d.c. If the charging current is not to exceed 3 A, what is the value of series resistance required?
(i) 20.2 Ω
(ii) 48.5 Ω
(iii) 33.2 Ω
(iv) 71.5 Ω

37. Masses of dissimilar substances activist in electrolysis through the similar quantity of electricity are proportional to
(i) atomic masses
(ii) valencies
(iii) ratio of atomic mass and valency
(iv) product of atomic mass and valency

38. A 6 V storage battery is being charged at pace of 20 C/s. Power use to charge battery is
(i) 12W
(ii) 120W
(iii) 66W
(iv) cannot be predicted

39. In over question, what percentage of energy taken as of the mains would be wasted?
(i) 90%
(ii 75%
(ii) 50%
(iv) 40%

40. Current flows 16 A flows through molten NaCl for 10 minutes. The quantity metallic sodium that appears at negative electrode likely (F = 96500 C/gram equivalent)
(i) 11.5g
(ii) 23g
(iii) 11.5g
(iv) 2.3g

41. Suppose that 10 A current deposits 10.8 g silver in 900 s. How much copper would be deposit through 9 A in 1200s?
(i) 5.8g
(ii) 38g
(iii) 11.8g
(iv) 7.9g

42. In order to attain 100 A for 10 seconds, one would use
(i) dry cell
(ii) lead-acid cell
(iii) Leclanche cell
(iv) none of the above

43. In order to find the E.C.E. of a substance, its chemical equal is multiply through E.C.E. of
(i) hydrogen
(ii) oxygen
(iii) carbon dioxide
(iv) sulphur

44. 965 C charge deposits 1.08 g of silver as passed through silver nitrate solution. What is chemical equal of silver?
(i) 108
(ii) 10.8
(iii) 1.08
(iv) none of the above

45. Battery of 3 V and internal resistance 1 Ω is joined to a copper voltameter. If a current of 15 A flows through die circuit, what is resistance of the voltameter?
(i) 1.5 Ω
(ii) 2 Ω
(iii) 2.5 Ω
(iv) 1 Ω

46. E.C.E. of a substance is mass of substance liberate at an electrode through ____ of current in half a second.
(i) 1 A
(ii) 2 A
(iii) 3 A
(iv) 4 A

47. Ampere hour is unit of
(i) electric current
(ii) electric charge
(iii) electric energy
(iv) electric power

48. Charge of 965 C is accepted through a silver voltameter. The quantity of silver deposit on the cathode is
(i) 0.59 g
(ii) 2.3 g
(iii) 1.08g
(iv) 3.2g

49. Car battery has 6 cells in series. What must be the near charging voltage?
(i) 10 V
(ii) 12 V
(iii) 100 V
(iv) 15 V

50. 1 A of current flow for 25 mm during a silver voltameter deposits 1.5 g of silver. The E.C.E. of silver is
(i) 0.001 g/C
(ii) 0.002 g/C
(iii) 0.06 g/C
(iv) 0.1 g/C

51. A battery of accumulators of e.m.f. 50 V and inside resistance 2 Ω is charged on a 100 V direct current mains. What sequence resistance will be necessary to give a charging current of 2A?
(i) 12.5 Ω
(ii) 8.4 Ω
(iii) 24.4 Ω
(iv) 23 Ω

52. In the over question, what is watt-hour efficiency?
(i) 75.52 %
(ii) 90.2 %
(iii) 83.71 %
(iv) 79.62 %

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