How is ethyl alcohol obtained from sweet fruits?Why is air excluded during this process?

Answer 1

the juice obtained frm the fruits is allowed to ferment.Bacteria which contain the enzymes invertase & zymase convert it into alcohol. Air is not required 4 the process as the bacteria r anaerobic.
Refer 2 cbse class 10 Sc. book

Answer 2

Via fermentation, in which the sugar in the fruit is converted to alcohol by yeast. Since yeast doesn't need ambient oxygen to do this, one can keep the air out to discourage competition from other organisms that need air and produce unwanted byproducts.

Answer 3

Ethanol for use in alcoholic beverages, and the vast majority of ethanol for use as fuel, is produced by fermentation: when certain species of yeast (most importantly, Saccharomyces cerevisiae) metabolize sugar in the absence of oxygen, they produce ethanol and carbon dioxide. The overall chemical reaction conducted by the yeast may be represented by the chemical equation

C6H12O6 → 2 CH3CH2OH + 2 CO2
The process of culturing yeast under conditions to produce alcohol is referred to as brewing. Brewing can only produce relatively dilute concentrations of ethanol in water; concentrated ethanol solutions are toxic to yeast. The most ethanol-tolerant strains of yeast can survive in up to about 25% ethanol (by volume).

During the fermentation process, it is important to prevent oxygen getting to the ethanol, since otherwise the ethanol would be oxidised to acetic acid (vinegar). Also, in the presense of oxygen, the yeast would undergo aerobic respiration to produce just carbon dioxide and water, without producing ethanol.

In order to produce ethanol from starchy materials such as cereal grains, the starch must first be broken down into sugars. In brewing beer, this has traditionally been accomplished allowing the grain to germinate, or malt. In the process of germination, the seed produces enzymes that can break its starches into sugars. For fuel ethanol, this hydrolysis of starch into glucose is accomplished more rapidly by treatment with dilute sulfuric acid, fungal amylase enzymes, or some combination of the two.

Answer 4

Alcohol fermentation.
The microbs used in the process are obligatory anaerobes(i.e. they cannot live in an environment having Oxygen(air)).
So the need to use anaerobic conditions.

Answer 5

molasses or cane sugar is mixed with water and yeast which contains invertase and zymase. the reaction can not take place in the presense of air as yeast is an anearobic bacteria.

Answer 6

alcohol fermentation.
it cannot happen if oxygen is around - the stuff will just rot instead.