Page 13 - E-LKM ACID BASE

Lembar Kerja Mahasiswa - Asam Basa

When strong acids dissolve in water. The acid is entirely ionized or
decomposed. For example, hydrochloric acid following:

+
HCl H + Cl -
(aq)
(aq)
(aq)
Consider what happens when hydrogen chloride is mixed into water:

Hydrogen chloride donates a hydrogen ion to one of the
nonbonding electron pairs on a water molecule, resulting in a third

hydrogen bonded to the oxygen. In this case, hydrogen chloride
behaves as an acid (proton donor) and water behaves as a base
(proton acceptor). The products of this reaction are a chloride ion
+
and a hydronium ion, H O , which, as Figure 7 shows, is made by
3
adding a proton (hydrogen ion) to a water molecule.

A strong acid has a weak conjugate base and vice versa. The
extend to which a dissolved substance can act as an acid or a base
depends largely on the solvent. The solute only shows acidic

properties if its proton-donating properties exceed those of the
solvent, and HF is forced to act as a base in liquid HClO as solvent
4

Mineral acids in water as solvent all have a much stronger tendency

to dona protons than does water. The mineral acids all donate
protons to the water, and ionize completely. Differentiating solvents
such as glacial acetic acid emphasize the difference in acidic
strength, and sever mineral acids are only partially ionized in this
solvent. This is because acele acid is a poor proton acceptor but a

rather better proton donor. This behaviour also means that a solute
which acts as a weak base in water behaves as strong base in acetic
acid: the solvent thus exerts a levelling effect on bases.

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