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Agriculture · Q191

Soil Science

Graduate and Post Graduate · Agriculture · question 191

Q191

Ligand adsorption of weak acid anion is maximum at a pH which is

A.
Equal to pK of weak acid
Answer
B.
Greater than 10 times of pK
C.
Less than 10 times of pK
D.
Independent of pK

Answer: Option A

Solution

Answer: Option A
Solution:
Ligand adsorption of weak acid anion is maximum at a pH that is equal to the pK of a weak acid. pK is a measure of the strength of an acid on a logarithmic scale. And pK value is given by log10(1/Ka), where Ka is the acid dissociation constant.
The mode of adsorption of ligands depends on the bond polarity of the linking atoms of the ligand.