A compound ‘X’ is a weak acid and it exhibits colour change at pH close to the equivalence point during neutralization of NaOH with CH₃COOH. Compound ‘X’ exists in ionized from in basic medium. The compound ‘X’ is

Question

What is the pH of a 0.1 M NaOH solution?

Answer 1

To determine the correct answer, we first need to understand the context provided in the question:

The compound ‘X’ is a weak acid and it exhibits a colour change at pH close to the equivalence point during the neutralization of NaOH with CH₃COOH.
Compound ‘X’ exists in ionized form in a basic medium.

Let's analyze each option:

Methyl Orange: Methyl orange is an indicator that changes color in the pH range of 3.1 to 4.4. It is not suitable for weak acid-weak base titrations because it changes color in a more acidic range.
Methyl Red: Methyl red changes color between pH 4.4 to 6.2, which is also lower than the typical equivalence point range for a weak acid-strong base titration.
Phenolphthalein: This is a suitable indicator for titrations involving weak acids like acetic acid (CH₃COOH) and strong bases like NaOH. It changes color in the pH range of 8.2 to 10. It exists in an ionized form in a basic medium, which matches the given details for compound ‘X’.
Eriochrome Black T: This is usually used in complexometric titrations, not for acid-base indicators at the mentioned pH levels.

Based on the analysis:

Phenolphthalein is the correct choice because it changes color in a suitable pH range for the titration of acetic acid (a weak acid) with sodium hydroxide (a strong base). The color change occurs near the equivalence point, and it exists in an ionized state in a basic medium.

Hence, the compound ‘X’ is Phenolphthalein.

Answer 2

To determine the correct answer, we first need to understand the context provided in the question:

The compound ‘X’ is a weak acid and it exhibits a colour change at pH close to the equivalence point during the neutralization of NaOH with CH₃COOH.
Compound ‘X’ exists in ionized form in a basic medium.

Let's analyze each option:

Methyl Orange: Methyl orange is an indicator that changes color in the pH range of 3.1 to 4.4. It is not suitable for weak acid-weak base titrations because it changes color in a more acidic range.
Methyl Red: Methyl red changes color between pH 4.4 to 6.2, which is also lower than the typical equivalence point range for a weak acid-strong base titration.
Phenolphthalein: This is a suitable indicator for titrations involving weak acids like acetic acid (CH₃COOH) and strong bases like NaOH. It changes color in the pH range of 8.2 to 10. It exists in an ionized form in a basic medium, which matches the given details for compound ‘X’.
Eriochrome Black T: This is usually used in complexometric titrations, not for acid-base indicators at the mentioned pH levels.

Based on the analysis:

Phenolphthalein is the correct choice because it changes color in a suitable pH range for the titration of acetic acid (a weak acid) with sodium hydroxide (a strong base). The color change occurs near the equivalence point, and it exists in an ionized state in a basic medium.

Hence, the compound ‘X’ is Phenolphthalein.

The Correct Option is C