Electrochemistry

JEE Main 2024 (Online) 27th January Morning ShiftNumericalEasy📈 Topic in 15% papers+4

Ques. 1JEE Main 2024, 27 January (Morning Shift)

The mass of silver (Molar mass of Ag : 108 g mol-1) displaced by a quantity of electricity which displaces 5600 mL of O2 at S.T.P. will be g.

Answer

108

Faraday's second law: equivalents of Ag = equivalents of O2

2H2O O2 + 4H+ + 4e- ⇒ 1 mol O2 = 4 F

Moles of O2 = 560022400 = 0.25 mol ⇒ charge = 0.25 × 4 = 1 F

Ag+ + e- Ag ⇒ 1 F deposits 1 mol Ag

∴ Mass of Ag = 1 × 108 = 108 g

Answer: 108

Ques. 2JEE Main 2024, 27 January (Evening Shift)

Which of the following statements is not correct about rusting of iron?

Rusting of iron is envisaged as setting up of electrochemical cell on the surface of iron object.
Dissolved acidic oxides SO2, NO2 in water act as catalyst in the process of rusting.
Coating of iron surface by tin prevents rusting, even if the tin coating is peeling off.
When pH lies above 9 or 10, rusting of iron does not take place.

Ques. 3JEE Main 2024, 27 January (Evening Shift)

The hydrogen electrode is dipped in a solution of pH = 3 at 25 . The potential of the electrode will be − 10-2 V. ( 2.303RTF = 0.059 V )

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