Question

Which cell was used as a power source in the Apollo Space Program? Write the chemical reactions taking place during the anodic and cathodic processes. Mention two advantages of such cells.

Answer 1

Hint:A fuel cell is a kind of device which converts the electrical energy into chemical energy through a chemical reaction.this is a part of electrochemistry.We should be aware of cathode and anode part in various cells to approach such questions.


Complete solution:
Alkaline fuel cell was used as a power source in the Apollo Space Program.
Alkaline Fuel Cell: Alkaline fuel cells consume hydrogen and pure oxygen, to produce potable water, heat, and electricity. They are among the most efficient fuel cells, having the potential to reach $70\% $ . The alkaline fuel cell (AFC), also known as the Bacon fuel cell after its British inventor, Francis Thomas Bacon, is one of the most developed fuel cell technologies
NASA has used alkaline fuel cells since the mid-1960s, in the Apollo-series missions and on the Space Shuttle.
Chemical reactions taking place during the anodic and cathodic processes:
The fuel cell produces power through a redox reaction between hydrogen and oxygen. At the anode, hydrogen is oxidized according to the reaction:
${H_2}\, + \,2O{H^ - }\,\, \to \,\,2{H_2}O\,\, + \,\,2{e^ - }$
producing water and releasing electrons. The electrons flow through an external circuit and return to the cathode, reducing oxygen in the reaction:
${O_2}\, + \,2{H_2}O\,\, + \,\,4{e^ - }\,\, \to \,\,2O{H^ - }\,\,$
producing hydroxide ions. The net reaction consumes one oxygen molecule and two hydrogen molecules in the production of two water molecules. Electricity and heat are formed as by-products of this reaction.
Advantages:
Alkaline fuel cell (AFC) technology has some significant advantages over other fuel cells: the ability to use lower quality hydrogen, a high efficiency, ability to work below ${0^ \circ }C$ , the possibility of using non noble catalysts, etc.
Alkaline fuel cells can be placed outside and started up at subfreezing temperatures without preheating.
It is highly efficient. And pollution free.


Note: AFCs are the cheapest of fuel cells to manufacture. The catalyst required for the electrodes can be any of a number of different chemicals that are inexpensive compared to those required for other types of fuel cells.
The commercial prospects for AFCs lie largely with the recently developed bi-polar plate version of this technology, considerably superior in performance to earlier mono-plate versions.