Question

choose the correct statement with respect to a fuel cell: a. it produces higher emissions than biodiesel - powered vehicles. b. it combines hydrogen and oxygen to produce water, and in the process produces electricity and heat. c. a fuel cell produces a voltage of about 1,000 volts. d. fuel cells are heavy and increase vehicle load.

Explanation:

• Option a: Fuel cells are known for their relatively low emissions compared to many traditional power sources like biodiesel - powered vehicles. Biodiesel combustion can produce various pollutants, while fuel cells (especially hydrogen - oxygen fuel cells) have cleaner by - products.
• Option b: In a hydrogen - oxygen fuel cell, the chemical reaction is \(2H_{2}+O_{2}\to2H_{2}O\). This reaction is an exothermic redox reaction. The energy released in the reaction is converted into electrical energy (through the movement of electrons in an external circuit) and heat.
• Option c: A single fuel cell typically produces a voltage in the range of 0.6 - 1.2 volts. To get higher voltages, fuel cells are often stacked together. A voltage of about 1000 volts from a single fuel cell is not typical.
• Option d: Fuel cells are designed to be relatively lightweight compared to some traditional power storage and generation systems (like large internal combustion engines with their associated components). They are intended to be efficient power sources without adding excessive weight.

Answer:

B. It combines hydrogen and oxygen to produce water, and in the process produces electricity and heat.