Faraday's Law of Electrolysis

IMPORTANT

Faraday's Law of Electrolysis: Overview

This topic covers concepts, such as, Faraday's Laws of Electrolysis, Faraday's First Law of Electrolysis, Current Efficiency & Equivalent Masses of Elements etc.

Important Questions on Faraday's Law of Electrolysis

EASY
IMPORTANT

Consider the reaction :

 Cr2O72-+14H++6e2Cr3++7H2O

The electricity in coulombs required to reduce 1 mol of   Cr 2 O 7 2 would be:

HARD
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A current of 1.70 A is passed through 300.0 mL of 0.160 M solution of ZnSO4 for 230 s with a current efficiency 90%. Find out the molaritymol L-1  of Zn2+after the deposition of Zn. Assume the volume of the solution to remain constant during the electrolysis.

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Calculate the quantity of electricity that would be required to reduce 12.3 g of nitrobenzene to aniline, if the current efficiency for the process is 50 per cent. If the potential drop across the cell is 3.0 volts, how much energy will be consumed?

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An acidic solution of Cu2+salt containing 0.4gofCu2+is electrolysed until all the copper is deposited. The electrolysis is continued for seven more minutes with the volume of solution kept at 100 mL and the current at 1.2 amp. The volume of gases evolved at NTP during the entire electrolysis:

MEDIUM
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In a fuel cell, hydrogen and oxygen react to produce electricity. In the process, hydrogen gas is oxidised at the anode and oxygen is reduced at the cathode. If 67.2 litre of H2 at STP react in 15 minutes, what is the average current produced? If the entire current is used for electro deposition of copper from copper II solution, how many grams of copper will be deposited?

Anode reaction: H2+2OH2H2O+2e

Cathode reaction: 12O2+H2O+2e2OH

MEDIUM
IMPORTANT

Chromium metal can be plated out from an acidic solution containing CrO3 according to the following equation.

CrO3 (aq)+6H+ (aq)+6eCr (s)+3H2O

Determine the following :

(i) The amount of chromium that will be plated out by 24,000 coulombs.

(ii) The time it will take to plate out 1.5 g of chromium by using 12.5 amp current.

HARD
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Chromium metal can be plated out from an acidic solution containing CrO3 according to the following equation:

CrO3 (aq)+6H+ (aq)+6eCr (s)+3H2O

Calculate:

(i) The amount of chromium that will be plated out by 24,000 coulombs.

(ii) The time it will take to plate out 1.5 g of chromium by using 12.5 A current.

HARD
IMPORTANT

An aqueous solution of NaCl on electrolysis gives H2(g), Cl2(g) and NaOH according to the reaction:

2Cl(aq)+2H2O2OH(aq)+H2(g)+Cl2(g).

A direct current of 25 amperes with a current efficiency of 62% is passed through 20 litres of NaCl solution (20% by weight). The reaction taking place at the anode and the cathode are:

Reaction at anode: 2ClCl2+2e

Reaction at cathode: 2H2O+2eH2+2OH

The time it will take to produce 1 kg of Cl2 and the molarity of the solution with respect to hydroxide ion would be (if it is assumed that there is no loss because of evaporation):

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The charge in coulombs of 1 gram of ion N3

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The electric charge for electrode deposition of one gram equivalent of a substance is:

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Faraday’s laws of electrolysis are related to the:

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Electrolysis of dilute aqueous NaCl solution was carried out by passing 10 milli ampere current. The time required to liberate 0.01 mol of  H2 gas at the cathode is (1 Faraday=96500  Cmol1):

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Aluminium oxide may be electrolysed at   1000°C to give Al metal (at mass = 27 amu, 1F = 96,500 C). To prepare 5.12 kg of Al would require

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A metal surface of 100 cm2 area has to be coated with nickel layer of thickness 0.001 mm. A current of 2A was passed through a solution of NiNO32 for x seconds to coat the desired layer. The value of x is _________. (Nearest integer)

(ρNi (density of Nickel) is 10 g mL1, Molar mass of Nickel is 60 g mol-1 F=96500 Cmol-1)

MEDIUM
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4 amp of current passed through acidified water for 30 min. The volume (in Litres) of hydrogen gas liberated at STP is

Round off the answer to the nearest integer.

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Two electrolytic cells one containing CuSO4 solution and the other containing ZnSO4 solution are connected in series. The same quantity of electricity is passed between the cells. Calculate the amount Cudeposited in CuSO4 cell if 13.1g of Zn is deposited in ZnSO4 cell. 

Report your answer upto one decimal place.

HARD
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Calculate the mass of benzene that would be required to produce a current of one ampere for three hours from following data

C6H6+152O26CO2+3H2O

EASY
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The weight of silver deposited when 0.2 faraday current is passed through silver nitrate solution.

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If 54 g of silver is deposited during an electrolysis reaction, how much aluminium will be deposited by the same amount of electric current?

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During the electrolysis of  conc. H2SO4, it was found that H2S2O8 and O2 were liberated in a molar ratio of 3:1. How many moles of H2 were found is terms of moles of H2S2O8?