Arun a class XII student remarked that diesel is being used worldwide for running trucks, buses, boats, ships, trains, etc. due to the presence of nitrogen and sulphur compounds in it, the exhaust gases contain oxides of nitrogen and sulphur which are the major pollutants in our environement. he discussed this problem with his teacher and suggested that in place of diesel, we can use biodiesel which is non-toxic as well as biodegradable.
After reading the above passage, answer the following questions:
(i) What is biodiesel andhow can it be prepared?
(ii) What is the by-product of the above process and how can it be used?
(iii) What values are expressed by Arun by Suggesting theuse of biodiesel in place of diesel?

Explanation

(i) Biodiesel is actually a mixture of ethyl esters of higher fatty acids. It can be prepared by trans-esterification of triglycerides present in oils and fats with ethanol in presence of NaOH or KOH at low temperature.

(ii) The by-product of the above process is glycerol which can be used in soaps and other industrial products.
(iii) The following environmental and economic concerns are displayed by arun.
* It is made from renewable biological resources such as vegetable oils (primarily soyabea and Jatropha, waste vegetable oils from restaurants and soe animal fats).
* Since biodiesel has extremely low sulphur content, it does not contribute to the formation of oxides of sulphur that produce acid rain.
* Less dependence an imported petroleum diesel thereby improving the economy of our country.
* The energy produced by combustion of biodiesel is almost the same as energy produced by petroleum diesel.