Electrolysis and Storage of Batteries - MCQ and answers

Electrolysis and Storage of Batteries - MCQ and answers

1. "The mass of an ion liberated at an electrode is directly proportional to the quantity of electricity".
The above statement is associated with
(a) Newton's law
(b) Faraday's law of electromagnetic
(c) Faraday's law of electrolysis
(d) Gauss's law
Ans: c

2. The charge required to liberate one gram equivalent of any substance is known as ______ constant
(a) time
(b) Faraday's
(c) Boltzman
Ans: b

3. During the charging of a lead-acid cell
(a) its voltage increases
(b) it gives out energy
(c) its cathode becomes dark chocolate brown in colour
(d) specific gravity of H2SO4 decreases
Ans: a

4. The capacity of a lead-acid cell does not depend on its
(a) temperature    
(b) rate of charge
(c) rate of discharge
(d) quantity of active material
Ans: b

5. During charging the specific gravity of the electrolyte of a lead-acid battery
(a) increases
(b) decreases
(c) remains the same
(d) becomes zero
Ans: a

6. The active materials on the positive and negative plates of a fully charged lead-acid battery are
(a)     lead and lead peroxide
(b)     lead sulphate and lead
(c) lead peroxide and lead
(d) none of the above
Ans: c

7. When a lead-acid battery is in fully charged condition, the colour of its positive plate is
(a) dark grey
(b) brown
(c) dark brown      
(d) none of above
Ans: c

8. The active materials of a nickel-iron battery are
(a)     nickel hydroxide
(6)     powdered iron and its oxide
(c) 21% solution of KOH
(d) all of the above
Ans: d

9. The ratio of ampere-hour efficiency to watt-hour efficiency of a lead-acid cell is
(a) just one
(b) always greater than one
(c) always less than one
(d) none of the above.
Ans: b

10. The best indication about the state of charge on a lead-acid battery is given by
(a) output voltage
(b) temperature of electrolyte
(c) specific gravity of electrolyte
(d) none of the above
Ans: c

11. The storage battery generally used in electric power station is
(a) nickel-cadmium battery
(b) zinc-carbon battery
(c) lead-acid battery
(d) none of the above
Ans: c

12. The output voltage of a charger is
(a) less than the battery voltage
(b) higher than the battery voltage
(c) the same as the battery voltage
(d) none of the above
Ans: b

13. Cells are connected in series in order to
(a)     increase the voltage rating
(6)     increase the current rating
(c) increase the life of the cells
(d) none of the above
Ans: a

14. Five 2 V cells are connected in parallel.
The output voltage is
(a) 1 V
(6) 1.5 V
(c) 1.75 V
(d) 2 V
Ans: d

15. The capacity of a battery is expressed in terms of
(a)     current rating
(b)     voltage rating
(e) ampere-hour rating
(d) none of the above
Ans: c

16. Duringthe charging and discharging of a nickel-iron cell
(a) corrosive fumes are produced
(b) water is neither formed nor absorbed
(c) nickel hydroxide remains unsplit
(d)     its e.m.f. remains constant
Ans: b

17. As compared to constant-current system, the constant-voltage system of charging a lead acid cell has the advantage of
(a) reducing time of charging
(b) increasing cell capacity
(c) both (a) and (b)
(d) avoiding excessive gassing
Ans: c

18. A dead storage battery can be revived by
(a) adding distilled water
(6) adding so-called battery restorer
(c) a dose of H2SO4
(d) none of the above
Ans: d
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19. As compared to a lead-acid cell, the efficiency of a nickel-iron cell is less due to its
(a) compactness
(b) lower e.m.f.
(c) small quantity of electrolyte used
(d) higher internal resistance
Ans: d

20. Trickle charging of a storage battery helps to
(a)     maintain proper electrolyte level
(b)     increase its reserve capacity
(c) prevent sulphation
(d) keep it fresh and fully charged
Ans: d

21. Those substances of the cell which take active part in chemical combination and hence produce electricity during
charging or discharging are known as______materials.
(a) passive
(b) active
(c) redundant
(d) inert
Ans: b

22. In a lead-acid cell dilute sulphuric acid (electrolyte) approximately comprises the following
(a) one part H2O, three parts H2SO4
(b) two parts H2O, two parts H2SO4
(c) three parts H2O, one part H2SO4
(d) all H2S04
Ans: c

23. It is noticed that durmg charging
(a)     there is a rise in voltage
(6)     energy is absorbed by the cell
(c) specific gravity of H2SO4 is increased
(d) the anode becomes chocolate brown in colour (PbCfe) and cathode be¬comes grey metallic lead (Pb)
(e) all of the above
Ans: e

24. It is noticed that during discharging the following does not happen
(a)     both anode and cathode become PbS04
(b)     specific gravity of H2SO4 decreases
(c) voltage of the cell decreases
(d) the cell absorbs energy
Ans: d

25. The ampere-hour efficiency of a leadacid cell is normally between
(a) 20 to 30%
(b) 40 to 50%
(c) 60 to 70%
(d) 90 to 95%
Ans: d

26. The watt-hour efficiency of a lead-acid cell varies between
(a) 25 to 35%
(b) 40 to 60%
(c) 70 to 80%
(d) 90 to 95%
Ans: c

27. The capacity of a lead-acid cell is measured in
(a) amperes
(b) ampere-hours
(c) watts
(d) watt-hours
Ans: b

28. The capacity of a lead-acid cell depends on
(a) rate of discharge
(b) temperature
(c) density of electrolyte
(d) quantity of active materials
(e) all above
Ans: e

29. When the lead-acid cell is fully charged, the electrolyte assumes _____ appearance
(a) dull
(b) reddish
(c) bright
(d) milky
Ans: d

30. The e.m.f. of an Edison cell, when fully charged, is nearly
(a) 1.4 V
(b) 1 V
(c) 0.9 V
(d) 0.8 V
Ans: a

31. The internal resistance of an alkali cell is nearly _____ times that of the lead-acid cell.
(a) two
(b) three
(c) four
(d) five
Ans: d

32. The average charging voltage for alkali cell is about
(a) 1 V
(b) 1.2 V
(c) 1.7 V
(d) 2.1 V
Ans: c

33. On the average the ampere-hour efficiency of an Edison cell is about
(a) 40%
(b) 60%
(c) 70%
(d) 80%
Ans: d

34. The active material of the positive plates of silver-zinc batteries is
(a) silver oxide      
(b) lead oxide
(c) lead
(d) zinc powder
Ans: a

35. Lead-acid cell has a life of nearly charges and discharges
(a) 500
(b) 700
(c) 1000
(d) 1250
Ans: d

36. Life of the Edison cell is at least
(a) five years
(b) seven years
(c) eight years
(d) ten years
Ans: a

37. The internal resistance of a lead-acid cell is _____ that of Edison cell
(a)    less than
(b)    more than
(c) equal to
(d) none of the above
Ans: a

38. Electrolyte used in an Edison cell is
(a) NaOH
(b) KOH
(c) HC1
(d) HN03
Ans: b

39. Electrolyte used in a lead-acid cell is
(a) NaOH
(b) onlyH2S04
(c) only water        
(d) dilute H2SO4
Ans: d

40. Negative plate of an Edison cell is made of
(a) copper
(b) lead
(c) iron
(d) silver oxide
Ans: c

41. The open circuit voltage of any storage cell depends wholly upon
(a) its chemical constituents
(b) on the strength of its electrolyte
(c) its temperature      
(d) all above
Ans: d
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