Na is used in reduction of Zn salt because from Chemistry Electr

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451.

Na is used in reduction of Zn salt because

  • Zn (oxi) > E°Na (oxi)

  • Zn (red) > E°Na (red)

  • Zn (oxi) < E°Na (oxi)

  • both (a) and (b)


C.

Zn (oxi) < E°Na (oxi)

Metals having higher oxidation potential (or lesser E°red) can replace metals having lesser oxidation potential.

Since, oxidation potential of Na is more than that of Zn. Therefore, Na is used to reduce Zn salts.


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452.

Reduction potentials of A, B, C and D are 0.8 V, 0.79 V, 0.34 V and -2.37 V respectively. Which element displaces all the other three elements?

  • B

  • A

  • D

  • C


453.

During the electrolytic reduction of alumina, the reaction at cathode is

  • 2H2O → O2 + 4H+ + 4e-

  • 3F- → 3F + 3e-

  • Al3+ + 3e- → Al

  • 2H+ + 2e- → H2


454.

One ampere of current is passed for 9650 seconds through molten AlCl3. What is the weight in grams of Al deposited at cathode? (atomic weight of Al = 27)

  • 0.9

  • 9.0

  • 0.09

  • 90.0


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455.

Molten CuCl2 is electrolysed using platinum electrodes. The reaction occurring at anode is

  • 2Cl- → Cl2 (g) + 2e-

  • Cl2(g) + 2e- → 2Cl

  • Cu2+ + 2e- → Cu (s)

  • Cu(s) → Cu2+ + 2e-


456.

During the electrolysis of cryolite, aluminium and fluorine are formed in ...... molar ratio :

  • 1:2

  • 2:3

  • 1:1

  • 1:3


457.

What is the reduction electrode potential (in volts) of copper electrode when [Cu2+] = 0.01 M is in a solution at 25°C?

(E° of Cu2+/ Cu electrode is + 0.34 V)

  • 0.3991

  • 0.2809

  • 0.3105

  • 0.3695


458.

The product obtained at anode when 50% H2SO4 aqueous solution is electrolysed using platinum electrodes is :

  • H2SO3

  • H2S2O8

  • O2

  • H2


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459.

0.066 g of metal was deposited when a current of 2 ampere is passed through a metal ion solution for 100 seconds. What is the electrochemical equivalent (in gram coulomb-1) of the metal ?

  • 3.3 × 10-6

  • 3.3 × 10-4

  • 0.033

  • 3.3


460.

When X amperes of current is passed through molten AlCl3 for 96.5 s, 0.09g of aluminium is deposited. What is the value of X?

  • 10 ampere

  • 20 ampere

  • 30 ampere

  • 40 ampere


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