Electrochemistry

Question

In a fuel cell, H₂ and O₂ react to produce electricity. In the process H₂ gas is oxidised at the anode and O₂ at cathode. If 67.2 litre of H₂ at STP reacts in 15 minutes, what is the average current produced? If the entire current is used for electro-deposition of Cu from Cu²⁺, how many grams of copper are deposited?

Solution

The redox changes in fuel cell are

2 H_{2} (g) + O_{2} (g) \to 2 H_{2} O (l)

At anode:

H_{2} + 2 {OH}^{-} \to 2 H_{2} O + 2 e

At cathode: $O_{2} + 2 H_{2} O + 4 e \to 4 {OH}^{-}$
Therefore, moles of

H_{2}

reacting

= \frac{67.2}{22.4} = 3

Therefore, equivalent of

H_{2}

used =

\frac{67.2}{22.4} = 3

Now,

\frac{w}{E} = \frac{i \times t}{96500}

Therefore,

6 = \frac{i \times 15 \times 60}{96500} i = 643.33 ampere

or
Also Eq. of

H_{2} = Eq . of Cu formed = 6 .

Hence,

W_{Cu} = \frac{6 \times 63.5}{2} = 190.5 g .

Some More Questions From Electrochemistry Chapter

Suggest a way to determine the Λ°_m value of water.

The molar conductivity of 0.025 mol L^–1methanoic acid is 46.1 S cm² mol^–1. Calculate its degree of dissociation and dissociation constant. Give λ°(H⁺) = 349.6 S cm²mol^–1 and λ° (HCOO^– ) = 54.6 s cm² mol^–1.

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Electrochemistry

Some More Questions From Electrochemistry Chapter

Suggest a way to determine the Λ°_m value of water.

The molar conductivity of 0.025 mol L^–1methanoic acid is 46.1 S cm² mol^–1. Calculate its degree of dissociation and dissociation constant. Give λ°(H⁺) = 349.6 S cm²mol^–1 and λ° (HCOO^– ) = 54.6 s cm² mol^–1.

If the current of 0.5 ampere flows through a metallic wire for 2 hours, then how many electrons flow through the wire?

Suggest a list of metals that are extracted electrolytically.

Consider the reaction: Cr₂O₇^2– + 14H⁺ + 6e- → 2Cr³⁺ + 8H₂O
What is the quantity of electricity in coulombs needed to reduce 1 mol of Cr₂O₇^2-?

Write the chemistry of recharging the lead storage battery, highlighting all the materials that are involved during recharging.

Suggest two materials other than hydrogen that can be used as fuels in fuel cells.

Name the electrolyte used in fuel cell?

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For Daily Free Study Material Join wiredfaculty

Electrochemistry

Some More Questions From Electrochemistry Chapter

Suggest a way to determine the Λ°m value of water.

The molar conductivity of 0.025 mol L–1 methanoic acid is 46.1 S cm2 mol–1. Calculate its degree of dissociation and dissociation constant. Give λ°(H+) = 349.6 S cm2 mol–1 and λ° (HCOO– ) = 54.6 s cm2 mol–1.

If the current of 0.5 ampere flows through a metallic wire for 2 hours, then how many electrons flow through the wire?

Suggest a list of metals that are extracted electrolytically.

Consider the reaction: Cr2O72– + 14H+ + 6e- → 2Cr3+ + 8H2OWhat is the quantity of electricity in coulombs needed to reduce 1 mol of Cr2O72-?

Write the chemistry of recharging the lead storage battery, highlighting all the materials that are involved during recharging.

Suggest two materials other than hydrogen that can be used as fuels in fuel cells.

Name the electrolyte used in fuel cell?

Mock Test Series

NCERT Sample Papers

Entrance Exams Preparation

Suggest a way to determine the Λ°_m value of water.

The molar conductivity of 0.025 mol L^–1methanoic acid is 46.1 S cm² mol^–1. Calculate its degree of dissociation and dissociation constant. Give λ°(H⁺) = 349.6 S cm²mol^–1 and λ° (HCOO^– ) = 54.6 s cm² mol^–1.

Consider the reaction: Cr₂O₇^2– + 14H⁺ + 6e- → 2Cr³⁺ + 8H₂O
What is the quantity of electricity in coulombs needed to reduce 1 mol of Cr₂O₇^2-?