Respuesta :
Solution:
According to the Henderson-Hasselalch equation:
TRIS-HCl + NaOH ---> TRIS + H2O + NaCl
Treat TRIS-HCl as a monoprotic acid, so there is a 1:1 molar ratio between TRIS-HCl and NaOH.
This the required answer.
Explanation:
According to Henderson-Hasselbalch equation:
pH = [tex]pK_{a} + log(\frac{[TRIS]}{[TRISH^{+}]})[/tex]
When pH = pKa = 8.
Therefore,
8 = 8 + [tex]log(\frac{[TRIS]}{[TRISH^{+}]})[/tex]
[tex]log(\frac{[TRIS]}{[TRISH^{+}]})[/tex] = 0
[tex]\frac{[TRIS]}{[TRISH^{+}]}[/tex] = [tex]10^0[/tex]
= 1
Hence, [TRIS] = [tex][TRISH^+][/tex]
As, fraction of amine groups converted to [tex]NH3^+[/tex]
= [tex]\frac{[TRISH^+]}{([TRISH+] + [TRIS])}[/tex]
= [tex]\frac{[TRISH^+]}{([TRISH+] + [TRISH^+])}[/tex]
= [tex]\frac{[TRISH^+]}{(2[TRISH^+])}[/tex]
= [tex]\frac{1}{2}[/tex]
= 0.5
Hence, we can conclude that fraction of the amine group coverted to [tex]NH3^{+}[/tex] is 0.5.
