NEETChemistryIonic Equilibrium
Match List I with List II for the selection of a suitable indicator in different acid-base titrations. List I (Titration) List II (Suitable Indicator) (A) HCl vs NaOH (I) Phenolphthalein (B) CH₃COOH vs NaOH (II) Methyl orange (C) HCl vs NH₄OH (III) Any of these (D) CH₃COOH vs NH₄OH (IV) None of these Choose the correct answer from the options given below:
Options
- A(A)-(III), (B)-(I), (C)-(II), (D)-(IV)
- B(A)-(III), (B)-(II), (C)-(I), (D)-(IV)
- C(A)-(I), (B)-(III), (C)-(II), (D)-(IV)
- D(A)-(I), (B)-(II), (C)-(III), (D)-(IV)
Correct answer
A. (A)-(III), (B)-(I), (C)-(II), (D)-(IV)
Step-by-step solution
Titration of a strong acid ( HCl ) and strong base ( NaOH ) has a sharp pH change from about 3 to 11 at the equivalence point, so any of these indicators (phenolphthalein or methyl orange) can be used. Titration of a weak acid ( CH₃COOH ) and strong base ( NaOH ) has an equivalence point in the basic region (pH > 7) due to anionic hydrolysis, making phenolphthalein (working range 8.0-9.8) suitable. Titration of a strong acid ( HCl ) and weak base ( NH₄OH ) has an equivalence point in the acidic region (pH Titration