Acid-catalysed addition (hydration)

Step 1 of 3

1. 1.The π electrons attack H⁺ from the acid catalyst.

An ethyl carbocation forms.

Step 2 of 3

1. 1.A lone pair on WATER attacks the carbocation. Not OH⁻ — there is no hydroxide in acid.

A protonated alcohol (with O⁺) forms.

Step 3 of 3

1. 1.An O–H bond breaks with both electrons returning to oxygen — H⁺ leaves and the catalyst is regenerated.

Ethanol forms and H⁺ returns to the catalyst pool.