Question

preparation of alkenes by the dehydration of ethyl alcohol(reactants,procedure,reaction)​

Answer 1

The dehydration reaction of alcohols to generate alkene proceeds by heating the alcohols in the presence of a strong acid, such as sulfuric or phosphoric acid, at high temperatures.

general rxn complete.png

The required range of reaction temperature decreases with increasing substitution of the hydroxy-containing carbon:

1° alcohols: 170° - 180°C

2° alcohols: 100°– 140 °C

3° alcohols: 25°– 80°C

If the reaction is not sufficiently heated, the alcohols do not dehydrate to form alkenes, but react with one another to form ethers (e.g., the Williamson Ether Synthesis).

ether.png

Alcohols are amphoteric; they can act both as acid or base. The lone pair of electrons on oxygen atom makes the –OH group weakly basic. Oxygen can donate two electrons to an electron-deficient proton. Thus, in the presence of a strong acid, R—OH acts as a base and protonates into the very acidic alkyloxonium ion +OH2 (The pKa value of a tertiary protonated alcohol can go as low as -3.8). This basic characteristic of alcohol is essential for its dehydration reaction with an acid to form alkenes.

alcohol base complete.

I think you got it

Answer 2

Explanation:

reactants:ethene or ethylene is prepared by the dehydration of ethyl alcohol.

procedure:ethyl alcohol is mixed with conc sulphuric acid and heated to about 170degree  celcius when the acid dehydrates the alcohol to form ethene.

reaction:C2H5OH(ABOVEARROW conc H2S04 at 170degree celcius)H2C(then double bond)CH2+H20

C2H5OH(ABOVE ARROW ON TOP AL203 BELOW 350 DEGREE CELCIUS)

collection:the gas is collected by dwnd displ of H20 as it is an inflammable gas and insoluble in water