Question

Which of the following statements is true for fuel cells?
(a) They are most efficient
(b) They are free from pollution
(c) They run till reactant are active
(d) All of the above

Answer 1

Hint: A fuel cell generates electricity cleanly and effectively by utilising the chemical energy of hydrogen or other fuels. Electricity, water, and heat are the only byproducts if hydrogen is the fuel.

Complete Step by Step Answer:
A fuel cell is a device that produces current, heat, and water by the electrochemical reaction between hydrogen and oxygen.
A fuel cell involves the following two half-cell reactions:
At anode: \[2{H_2} + 4O{H^ - } \to 4{e^ - } + 4{H_2}O\]
At cathode: \[O2 + 2{H_2}O + 4{e^ - } \to 4O{H^ - }\]
Therefore, a complete cell reaction: \[2{H_2} + {O_2} \to 2{H_2}O + Energy\]
The hydrogen acts as a fuel consumed in a fuel cell at the anode. whereas oxygen also acts as a fuel cell consumed at the cathode.

From the cell reaction, it is also clear that they are highly efficient i.e., the longevity of the fuel cell depends upon the supply of the reactants (\[{H_2}\] and \[{O_2}\]). Therefore, fuel cells run till reactants are supplied. Because the fuel cells generate water. And we all know that water is very vital for all the beings on earth. Hence, the fuel cells do not cause pollution for our environment.

The above points indicate that fuel cells are the most efficient, environmentally friendly, and reactant-dependent life span. Therefore, the answer is (d).

Note: Fuel cells can be used in various applications, such as transportation, material handling, and emergency backup power. The high cost of platinum, and lack of distribution of hydrogen are the main limitation for the making of a fuel cell.