Question

Match List I with List II, and

List I Volumetric Solution		List II Primary Standard
A	0.1 M Iodine	I	Potassium iodate
B	0.1M Sodium thiosulphate	II	Potassium bromate
C	0.1M Sodium hydroxide	III	Potassium hydrogen phthalate
D	0.1M Perchloric acid	IV	Arsenic trioxide
		V	Potassium hydrogen phthalate

Choose the correct answer from the options given below:

• A. A ‐ IV, B ‐ II, C ‐ III, D ‐ V
• B. A ‐ IV, B ‐ II, C ‐ III, D ‐ I
• C. A ‐ I, B ‐ IV, C ‐ II, D ‐ III
• D. A ‐ III, B ‐ II, C ‐ IV, D ‐ I

Answer 1

The Correct Option is A

To correctly match List I (Volumetric Solutions) with List II (Primary Standards), we must understand what each substance is used for:

1. 0.1 M Iodine (A): This is typically used in redox titrations. The primary standard associated with iodine is Arsenic trioxide (IV) because Arsenic trioxide is used to standardize iodine solutions.
2. 0.1 M Sodium thiosulphate (B): This solution is also used in redox titrations, often to standardize iodine. The primary standard relevant here is Potassium bromate (II), used in iodometric titrations to generate iodine in situ, which can then be titrated with sodium thiosulphate.
3. 0.1 M Sodium hydroxide (C): This is a common basic solution used to titrate acids. It is standardized using Potassium hydrogen phthalate (III), which acts as the primary standard because it is stable, pure, and typically has a defined equivalent point.
4. 0.1 M Perchloric acid (D): This is often used for titrating bases and is standardized using a primary standard like Potassium hydrogen phthalate (V), due to its stable nature and known acidic properties.

After the analysis, we find that the correct matches are:

• A - IV: 0.1 M Iodine is matched with Arsenic trioxide.
• B - II: 0.1 M Sodium thiosulphate is matched with Potassium bromate.
• C - III: 0.1 M Sodium hydroxide is matched with Potassium hydrogen phthalate.
• D - V: 0.1 M Perchloric acid is matched with Potassium hydrogen phthalate.

Thus, the correct answer is:

A ‐ IV, B ‐ II, C ‐ III, D ‐ V