State the "physical interpretation" of pka

pka = -logKa

Explanation:

pKa is defined as negative logarithm of dissociation constant, Ka.

Or, pka = -logKa

pKa define strength of an acid.

Higher pKa indicates lower strength of the acid or low dissociation of the acid.

Whereas lower pKa indicates higher strength of the acid or high dissociation of the acid.

pKa is also related with pH of the solution.

Higher the pKa, higher is the pH of the solution. This can be understood as:

Higher pKa means lower dissociation dissociation or low concentration of H+. Low H+ means high pH.

Relation between pKa and pH is given by Henderson-Hasselbalch equation,