Ethene reacts with concentrated tetraoxosulphate (VI) acid to form ethyl hydrogen tetraoxosulphate (VI).

$$\text{C}_2\text{H}_5\text{HSO}_{4(aq)} + \text{H}_2\text{O}_{(l)} \longrightarrow \text{C}_2\text{H}_5\text{OH}_{(aq)} + \text{H}_2\text{SO}_4$$

Other Methods of Preparing Ethanol in the Laboratory:

1. By hydration: Ethene is mixed with steam in the presence of $\text{H}_2\text{SO}_4$ as a catalyst at $600^\circ\text{C}$ and $80 \text{ atm}$.

   $$\text{C}_2\text{H}_{4(g)} + \text{H}_2\text{O}_{(g)} \xrightarrow{600^\circ\text{C}, 80 \text{ atm}, \text{H}_2\text{SO}_4} \text{C}_2\text{H}_5\text{OH}_{(aq)}$$

2. Reducing of ethanal: Ethanal is reduced using nascent hydrogen in the presence of a nickel catalyst.

   $$\text{CH}_3\text{CHO}_{(g)} + \text{H}_{2(g)} \longrightarrow \text{C}_2\text{H}_5\text{OH}_{(aq)}$$

3. By hydrolysis of iodoethane: Iodoethane undergoes hydrolysis using alkalis.

   $$\text{C}_2\text{H}_5\text{I}_{(l)} + \text{NaOH}_{(aq)} \longrightarrow \text{C}_2\text{H}_5\text{OH}_{(aq)} + \text{NaI}_{(s)}$$

4. By hydrolysis of esters: Esters are hydrolyzed using hot alkalis.

   $$\text{CH}_3\text{COOC}_2\text{H}_{5(aq)} + \text{NaOH}_{(aq)} \longrightarrow \text{C}_2\text{H}_5\text{OH}_{(aq)} + \text{CH}_3\text{COONa}_{(s)}$$

Industrial Preparation of Ethanol:

Ethanol is produced commercially by a process involving the breaking down or slow decomposition of complex organic matter.