Question
Question: A certain indicator (an organic dye) has pKa = 5. For which of the following titrations may it be su...
A certain indicator (an organic dye) has pKa = 5. For which of the following titrations may it be suitable.
A
Acetic acid against NaOH
B
Aniline hydrochloride against NaOH
C
Sodium carbonate against HCl
D
Barium hydroxide against oxalic acid
Answer
Sodium carbonate against HCl
Explanation
Solution
pKHIn = 5
(1) CH3COOH + NaOH, end point pH > 7
(2) Auillne hydrochloride + NaOH, end point pH > 7
(3) NaHCO3 + HCI, end point pH < 7
(4) Ba(OH)2 + H2C2O4 , end point pH > 7