<prompt> pKApH when:Solute is completely ionisedWhen the concentration of ionised and unionized form is sameSolute is completely unionizedAll of the above  <response>: Ans. B. When the concentration of ionized and unionized form is sameThis question is an application of Henderson Hasselbalch equation.It ispHpKalog is concentration of ionised form is concentration of unionised form.When , thenpHpKalogpHpKalog1i.e.pHpKa0 