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AP EAMCET · Chemistry · Ionic Equilibrium

In an amino acid, the carboxylic group ionises at \(\mathrm{pH}=2.56\left(\mathrm{pK}_{\mathrm{a}_1}\right)\) and ammonium ion ionises at \(\mathrm{pH}=9.38\left(\mathrm{pK}_{\mathrm{a}_2}\right)\). The isoelectric point of the amino acid is at

  1. A 11.94
  2. B 6.82
  3. C 5.97
  4. D 3.41
Verified Solution

Answer & Solution

Correct Answer

(C) 5.97

Step-by-step Solution

Detailed explanation

\(\mathrm{p} K_{a 1}=256, \mathrm{p} K_{a_2}=9.38\) At isoelectric point \[ (\mathrm{pH})=\frac{\mathrm{p} K_{a_1}+\mathrm{p} K_{a_2}}{2}=\frac{2.56+9.38}{2}=5.97 \]