[yeung]

When ethanol is dripped on a blue litmus paper,will it turn red due to the hydrogen ions formed?

[xiankai]

ethanol's hydrogen bonds are covalent in nature and hence, do not dissociate. the hydroxyl functional group however, does and thus turns red litmus paper blue instead.

[yeung]

Does it mean that only the  atoms in the functional group of a molecule can form ions?

[xiankai]

actually, i think of a functional group as the part of a molecule that is "reactive" and will dissociate into ions and stuff like that.

the other atoms in the molecule may be able to form ions, but are probably too tightly bonded to the molecule to react. with optimal conditions they may do so. im not so sure about this.

[Borek]

ethanol's hydrogen bonds are covalent in nature and hence, do not dissociate. the hydroxyl functional group however, does and thus turns red litmus paper blue instead.

Are you sure about it? Ethanol can behave like an acid, it even has a measurable Ka, but it is so weak, that for most practical purposes it should be treated as non-dissociating, neutral compound.

[xiankai]

u mean the H+ found in the hydroxyl group?

[Borek]

u mean the H+ found in the hydroxyl group?

Yes.