Question

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 : $2H_2+4\stackrel{\ominus }{O}H\to 4H_{2}O\left(l\right)+4e^{-}$

Cathode : $O_2+2H_{2}O\left(l\right)+4e^{-}\to 4\stackrel{\ominus }{O}H$

IV. The efficiency of $H_2-O_2$ fuel cell is $70$ to $75\%$.

• A. $I,III$
• B. $I,III,IV$
• C. $I,II,III,IV$
• D. $I,II,III$

Answer 1

The correct option is C $I,II,III,IV$

R.E.F image

It is possible to make batteries in which the reactants are fed continuously to the electrodes. Electrical cells that are designed to convert the free energy from the combustion of fuels such as hydrogen, carbon monoxide or methane directly into electrical energy are called FUEL CELLS. One of the most successful fuel cells uses the reaction of hydrogen with oxygen to form water (fig.). This cell has been used for electric power in the Appollo space programme. The water vapour produced was condensed and added to the drinking water supply for the astronauts. In the cell (fig.) hydrogen and oxygen are bubbled through a porous carbon electrode into concentrated aqueous sodium hydroxide. Catalysts are incorporated in the electrode. The electrode reactions are:

Anode: $2\times \left[H_2\right(g)+2O{H}^{-}(aq)\to 2H_{2}O(l)+2e^{-}]$

Cathode: $O_2\left(g\right)+2H_{2}O\left(l\right)+4e^{-}\to 4O{H}^{-}\left(aq\right)$

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Overall reactions: $2H_{2}g+O_2\left(g\right)\to 2H_{2}O\left(l\right)$

All the statements are true.