Question

which of the following best describes the method of vehicle transport that is the most environmentally sustainable?
a the use of a vehicle powered by hydrogen fuel cells because there are no carbon emissions
b the use of a plug - in hybrid vehicle because the fuel sources do not release any carbon dioxide
c the use of a vehicle powered by biodiesel because it can be used in conjunction with traditional diesel
d the use of a vehicle powered by ethanol because corn is grown to produce energy rather than for human consumption

Explanation:

• Option A: Hydrogen fuel - cell vehicles produce water as a by - product (\(2H_2+O_2 = 2H_2O\)) and no carbon emissions. This is highly environmentally sustainable as carbon emissions contribute to climate change.
• Option B: Plug - in hybrid vehicles still use some fossil fuels (even if they also use electricity). The production of electricity may involve some carbon - emitting processes (depending on the energy source for electricity generation), and they do release some carbon dioxide when running on the fuel part of the hybrid system.
• Option C: Biodiesel, when burned, still releases carbon dioxide (\(C_nH_{2n + 2}+(3n + 1)/2O_2=nCO_2+(n + 1)H_2O\)). Although biodiesel is a renewable fuel (as the plants that produce it can be regrown), it is not carbon - neutral in the strictest sense (there are carbon emissions during production and combustion), and using it with traditional diesel still has carbon - related environmental impacts.
• Option D: Using corn for ethanol production can lead to issues such as using land that could be used for food production. Also, the production and combustion of ethanol (\(C_2H_5OH+3O_2 = 2CO_2+3H_2O\)) release carbon dioxide.

Answer:

A. The use of a vehicle powered by hydrogen fuel cells because there are no carbon emissions.