Chemistry - What is the OH in alcohol?

Solution 1:

You could call ethyl alcohol "ethyl hydroxide" analogously to "sodium hydroxide". But it is a poor analogy, since (unlike NaOH) ethyl alcohol is not an ionic compound, does not dissociate in water to form ethyl cation and hydroxide anion, and does not raise the pH when dissolved in water.

Solution 2:

Well, I don’t understand what you are trying to ask.

But the $\ce{OH}$ you are bothered about can be thought exactly as that of $\ce{OH}$ of water ($\ce{H2O}$)

$\ce{C2H5-OH}$ in the same way as $\ce{H-OH}$

Solution 3:

Many people confuse between the three forms of the OH group.

When the OH has a negative charge, it is called hydroxide, and it forms ionic compounds with cations. An example is sodium hydroxide, which contains discrete Na+ ions and OH- ions. When dissolved in water, it separates into Na+ ions and OH- ions (solvation not mentioned for simplicity)

When the OH forms a covalent bond (different from the ionic bond above) with any other group, it is called a hydroxy group. An example is ethanol, H3C-CH2-OH, the oxygen in the OH forming a covalent bond with the carbon in the ethyl group. When you dissolve ethanol in water, it does not separate into C2H5+ and OH- ions like the NaOH would.

The final form of the OH is called a hydroxyl radical. Imagine removing an electron from a negatively charged hydroxide ion to make it charge-neutral. In this form it is very, very reactive, as it lacks an electron to achieve the stable form of hydroxide (like how a halogen behaves).