Question

What is the levelling effect?

Answer 1

Levelling effect of a particular solvent is used in the comparison of the acidic or basic strength of the acids or base. But the levelling effect is not shown by each and every solvent. Water shows levelling effect and hence, we can compare the acidic and basic strength with the help of ions like ${H_3}{O^{ + \;}}$ and $O{H^{ - \;}}$ ions respectively.

Complete answer:
We know that the acidity or basicity of acid or base conjointly depends on the solvent. This is often the fundamental principle of levelling effect. In keeping with this, the strength of acid may be levelled by the basicity of the solvent. Equally we are able to say that the strength of base may be levelled by acidity of solvent. After we dissolve a powerful acid in water solvent then it forms ${H_3}{O^ + }$ ions.
Therefore, any acid that is stronger than ${H_3}{O^ + }$ can react with water and type ${H_3}{O^ + }$ ions. Thus we are able to say that no acid stronger than ${H_3}{O^ + }$ particle will exist in water solvent. Now, we can say that, once ammonia may be a solvent, the strongest acid is going to be ammonium and thus HCl exert a similar result. A similar condition is for bases conjointly. Thus, we can say that the basicity of the solvent can level the strength of sturdy acid and acidity of the solvent will level the strength of weak acid. Therefore, acids that square measure stronger than ${H_3}{O^ + }$ and also the bases that square measure stronger than $O{H^{ - \;}}$ are going to be levelled by water solvent. Thus $N{H_2}$ and ${H^ - }$ show levelling effects and have a similar base strength. Alternative solvents like ammonia conjointly show this levelling result.

Note:
We should remember that the levelling effect is additionally referred to as the solvent effect of acid-base. This impact is just valid for a few solvent like water and ammonia. For acidity we compare the ${H_3}{O^ + }$ ions of the acids and for base we compare the $O{H^{ - \;}}$ ions of base. This effect is used to determine the strength of acids and bases.