Why is `K_(2)Cr_(2)O_7` generally preferred over `Na_(2)Cr_(2)O_(7)` , in volumetric analysis though both are oxidising agents ?

Explanation

To answer the question of why potassium dichromate (K₂Cr₂O₇) is generally preferred over sodium dichromate (Na₂Cr₂O₇) in volumetric analysis, despite both being oxidizing agents, we can break down the reasoning into several steps:

### Step-by-Step Solution:

1. **Understanding the Compounds**:
- Both K₂Cr₂O₇ and Na₂Cr₂O₇ are dichromates and serve as oxidizing agents in chemical reactions. However, their physical properties differ.

2. **Hygroscopic Nature of Sodium Dichromate**:
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