Chemistry XII - ElectroChemistry 08

Question : 1

(skipped)

In dry cell, anode and cathode respectively is

Options:

	Zn and graphite
	Graphite and Zn
	Nickel and copper
	Copper and nickel

Solution :

(1)

Anode is Zn and cathode is graphite

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Question : 2

(skipped)

The electrolyte used in mercury cell is

Options:

	Paste of NH4Cl and ZnCl2
	Moist HgO mixed with KOH
	Conc. KOH
	Paste of MnO2 and KOH

Solution :

(2)

Electrolyte is moist HgO mixed with KOH.

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Question : 3

(skipped)

Lead storage battery is

Options:

	Primary cell
	Fuel cell
	Secondary cell
	Dry cell

Solution :

(3)

Lead storage battery can be recharged.

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Question : 4

(skipped)

The cell reaction occurs during discharging in lead storage battery is

Options:

	2PbSO4 + 2H2O → PbO2 + Pb + 4H+ + 2SO4–2
	PbO2 + 4H+ + SO4–2 + 2e → PbSO4 + 2H2O
	Pb + SO4–2 → PbSO4 + 2e
	PbO2 + Pb + 4H+ + 2SO4–2 → 2PbSO4 + 2H2O

Solution :

(4)

The net cell reaction is

PbO₂ + Pb + 4H⁺ + 2SO₄^–2 → 2PbSO₄ + 2H₂O

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Question : 5

(skipped)

Which of the following factors promote corrosion?

Options:

	Reactivity of metals
	Presence of air and moisture
	Presence of electrolyte
	All of these

Solution :

(4)

All promote the corrosion.

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Question : 6

(skipped)

Which of the following is used as anti-rust solution?

Options:

	Alkaline phosphate and alkaline chromate solutions
	Acidic phosphate and acidic chromate solutions
	Neutral phosphate and neutral chromate solutions
	Solution of NaCl and CuSO4

Solution :

(1)

Alkaline phosphate and alkaline
chromate solution is used as anti-rust
solution

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Question : 7

(skipped)

In rusting of iron, which of the following act as electrolyte?

Options:

	AlCl3 (anhyd)
	Moist N2
	Moist CO2
	Moist H2

Solution :

(3)

CO₂ + H₂O → H₂CO₃

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Question : 8

(skipped)

The cell potential and efficiency of hydrogen-oxygen fuel cell respectively is

Options:

	1.2 volt and 80-90%
	0.5 volt and 85-95%
	1.4 volt and 70-80%
	0.9 volt and 60-70%

Solution :

(4)

Actual efficiency = 60–70%
and cell potential = 0.9 V

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Question : 9

(skipped)

Which of the following statement is correct?

Options:

	Nickel-cadmium cell has longer life than the lead storage cell
	A 48% solution of sulphuric acid is used as an electrolyte in lead storage battery
	In corrosion, a metal is reduced by gain of electrons
	All of these

Solution :

(1)

]Nickel-cadmium cell has longer life than
lead storage battery.

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Question : 10

(skipped)

Which of the following reaction does not occur in rusting or iron?

Options:

	Fe → Fe+2 + 2e
	O2 + 2H2O + 4e– â†’ 4OH–
	2Fe2O3 + 8H+ â†’ 4Fe+2 + O2 + 4H2O
	Fe2O3 + xH2O → Fe2O3â‹…xH2O

Solution :

(3)

Metal does not reduce.