The table shows properties of some fuels - HSC - SSCE Chemistry - Question 25 - 2004 - Paper 1

Ethanol, as indicated in the table, has a heat of combustion of 29.7 kJ/g, which is significantly lower than that of other fuels such as methane (55.6 kJ/g) and propane (50.3 kJ/g). This suggests that ethanol produces less energy upon combustion, which may limit its efficiency as a fuel choice.

Additionally, ethanol has a boiling point of 78.3 °C, which is higher than that of methane and propane, making it less volatile and possibly more difficult to ignite under certain conditions. However, ethanol's production via fermentation and hydration of ethene offers a renewable source, contributing to sustainability goals.

Moreover, ethanol's lower carbon footprint compared to fossil fuels positions it as a favorable alternative in the context of reducing greenhouse gas emissions. Nevertheless, its lower heat of combustion means that more ethanol would be required to produce the same energy output as traditional fuels, which could lead to increased fuel consumption.

In conclusion, while ethanol presents advantages in terms of sustainability and lower emissions, its comparative inefficiency in energy yield must be considered when assessing its practicality as an alternative fuel.