Name: Gibbs Free Energy, EMF and Equilibrium Constant
Uploaded: 2019-07-19
Duration: 6 min 15 s
Description: There are various thermodynamic parameters that are to be considered while studying the working of an electrochemical cell. Let's learn about them here!

Question

What is fuel cell? Give the construction and working of a fuel cell.

Accepted Answer

Conventional batteries supply electrical energy from the chemical reactants stored within them; when these reactants are consumed, the battery is "dead". An alternative approach would be to feed the reactants into the cell as they are required, so as to permit the cell to operate continuously. In this case the reactants can be thought of as "fuel" to drive the cell, hence the term fuel cell.

In a fuel cell, the fuel is oxidized at the anode which yields electrons that flow through an external circuit doing electrical work, before an oxidant (often oxygen) is reduced by these electrons at the cathode. $O_{2} (g) + H_{2} (g) Fuel \to 2 H_{2} O (l)$

difference to be generated between the two electrodes

$The working of this fuel cell involved the passing of hydrogen and oxygen into a concentrated solution of sodium hydroxide via carbon electrodes . The cell reaction can be written as follows : H 2 (g) \to 2 H + + 2 e - E ° = 0 v anode - oxidation occurs ½ O 2 + 2 H + + 2 e - \to H 2 O (l) E ° = + 1.23 v cathode - reduction occurs H 2 (g) + ½ O 2 (g) \to H 2 O (l) E ° = + 1.23 v$

A fuel cell is a special type of battery in which the reactants are supplied from an external source as power is produced. In most practical fuel cells, hydrogen ions are produced at the anode (either from Hydrogen gas or a hydrocarbon) and oxygen from the air is reduced to water at the cathode. It is eco-friendly as the by-product is water and does not harm atmosphere and is pollution free device.

Note-The resulting electricity can be used in a variety of ways, including: powering motor vehicles, electrical devices, and airplanes. Fuel cells also produce heat as a by-product which is finding increasing use in heating homes, especially in Japan. With its multifunctional products and by-products, fuel cells are rapidly becoming the hot ticket alternative source of energy as we move into a greener and more progressive era.At the time, it was already known that water could be decomposed into hydrogen and oxygen by electrolysis; Grove tried recombining the two gases in a simple apparatus, and discovered what he called "reverse electrolysis"— that is, the recombination of H₂ and O₂ into water— causing a potential

What is fuel cell? Give the construction and working of a fuel cell.

Important Questions on Electrochemistry

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