For a fuel cell, which statementis correct? from Chemistry Elect

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 Multiple Choice QuestionsMultiple Choice Questions

171.

How much Coulomb needed to convert 1 mole of MnO4
into Mn2+?

  • 482500 C

  • 193000 C

  • 96500 C

  • 36500 C


172.

Aluminium is extracted by the electrolysis of

  • alumina

  • bauxite

  • molten cryolite

  • alumina mixed with molten cryolite


173.

Saturated solution of KNO3 is used to make salt bridge because

  • KNO3 is highly soluble in water

  • velocity of K+ is greater than that of NO3-

  • Velocity of NO3- 1s greater than that of K+

  • velocity of K+ and NO3- are almost equal


174.

Which of the following is a highly corrosive salt?

  • FeCl2

  • PbCl2

  • Hg2Cl2

  • HgCl2


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175.

One Faraday of charge passes through solution of AgNO3 and CuSO4 connected in series and the concentration of two solutions being in the ratio 1 : 2. The ratio of amount of Ag and Cu deposited on Pt electrode is

  • 1079.6354

  • 54.3177

  • 1079.3177

  • 54.6354


176.

On passing 0.5 Faraday of electricity through NaCl, the amount of Cl deposited on cathode is

  • 35.5 g

  • 17.75 g

  • 71 g

  • 142 g


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177.

For a fuel cell, which statementis correct?

  • Hydrogen is oxidised to H2O at cathode

  • Oxygen is reduced to OH- at anode

  • Hydrogen is oxidised to H2O at anode

  • Hydrogen is oxidised to H+ at anode


C.

Hydrogen is oxidised to H2O at anode

Galvanic cells which use energy for combustion of fuels like H2, CH4, CH3OH etc as the source to produce electncal energy are called fuel cells Fuel cell uses the reaction of H2 and O2 in gaseous state to form water.

At anode, hydrogen is oxidised to H2O

(i) 2H2 → 4H+ + 4e-

(ii) 4H+ + 4OH- → 4H2O

At cathode, oxygen is reduced to OH ions.  O2(g) + 2H2O (l) + 4e-  4OH(aq)


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178.

An example for a strong electrolyte is

  • urea

  • ammonium hydroxide

  • sugar

  • sodium acetate


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179.

2 × 10-5C charge on Zn2+  ions corresponds to

  • 2 × 10-5 mol of Zn2+ ions

  • 6.22  × 107 Zn2+ ions

  • 0.64 mg of Zn2+ ions

  • 1 × 10-10 mol Zn2+ ions.


180.

What is the.standard potential of the Tl3+/ Tl electrode?

Tl3+ +2e- → Tl+, E°= 1.26V

Tl+ +e- → Tl, E°=-0.336V

  • 0.924V

  • -0.924 V

  • 0.728 V

  • -0.728V


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