What are 'fuel cells'? Write cathode and anode reaction in a fuel cell.

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Solution

Fuel cells:
These are galvanic cells in which the energy of combustion of fuels is directly converted into electrical energy. Commonly used fuels are hydrogen, methanol etc.
The half cell reactions in hydrogen - oxygen fuel cell are given below.
Oxidation at anode:
$H y d r o g e n$ gas and $h y d r o x i d e$ ions are oxidised to $w a t e r$ .
$2 H_{2} (g) + 4 O H^{-} (a q) \to 4 H_{2} O (l) + 4 e^{-}$
Reduction at cathode:
$O x y g e n$ gas and $w a t e r$ molecules are reduced to $h y d r o x i d e$ ions.
$O_{2} (g) + 2 H_{2} O (l) + 4 e^{-} \to 4 O H^{-} (a q)$

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Similar questions

A fuel cell is:

I.A voltaic cell in which continuous supply of fuels are sent at anode to perform oxidation.

II. A voltaic cell in which fuels such as :

$C H_{4}, H_{2}$ and CO are used up at anode.

III. One which involves the reaction of $H_{2} O_{2}$ fuel cell such as:

Anode : $2 H_{2} + 4 ⊖ O H \to 4 H_{2} O (l) + 4 e^{-}$

Cathode : $O_{2} + 2 H_{2} O (l) + 4 e^{-} \to 4 ⊖ O H$

IV. The efficiency of $H_{2} - O_{2}$ fuel cell is $70$ to $75 %$ .

H_{2} - O_{2}

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