Question

Based on your knowledge of titration curves determine the best choice of the following options.

	A.	In the titration of a weak acid with a strong base, the pH=pKa when the titration is halfway to the equivalence point. This is the half titration point.
	B.	At the half titration point, the moles of weak acid equals the moles of added base.
	C.	At the half titration point, the moles of weak acid (HA) and it's conjugate base (A–) are equal.
	D.	If [HA]=[A–], then according to the Henderson-Hasselbalch equation the pH=pKa.
	E.	More than one of the statements (A–D) are correct.
	F.	All of the statements (A–D) are correct.

Answer 1

A) In the titration of a weak acid with a strong base, the pH=pKa when the titration is halfway to the equivalence point. This is the half titration point.

the above statement is true

B) At the half titration point, the moles of weak acid equals the moles of added base .

this is incorrect , because   the moles of weak acid equals the moles of added base at equivalence point .

C) At the half titration point, the moles of weak acid (HA) and it's conjugate base (A–) are equal.

this is correct

D) If [HA]=[A–], then according to the Henderson-Hasselbalch equation the pH=pKa.

As

Henderson-Hasselbalch equation pH =pKa + log [A-]/[HA]

As [A-]= [HA]

  pH =pKa + log [A-]/[A-] = pKa + log (1)

pH=pKa

hence D) is also correct

so the correct option is

e) More than one of the statements (A–D) are correct.