Question

Read the following two statements:
Statement I: Potassium dichromate is used in volumetric analysis.
Statement II: \(K_2Cr_2O_7\) is more soluble in water than \(Na_2Cr_2O_7\)

• A. Both statements I and II are correct.
• B. Both statements I and II are incorrect.
• C. Statement I is correct and II is incorrect
• D. Statement I is incorrect and II is correct.

Hint:

\(K_2Cr_2O_7\) is preferred as a primary standard in volumetric analysis due to its stability and consistency in aqueous solutions, even though it has lower solubility compared to \(Na_2Cr_2O_7.\)

Answer 1

The Correct Option is C

To determine the correctness of the given statements, let's analyze them individually:

1. Statement I: Potassium dichromate is used in volumetric analysis.
   • Explanation: Potassium dichromate \((K_2Cr_2O_7)\) is a well-known oxidizing agent used in volumetric analysis. It is preferred due to its stability and non-hygroscopic nature. In titrations, it serves as a primary standard for measuring the concentration of reducing agents.
   • Conclusion: This statement is correct.
2. Statement II: \(K_2Cr_2O_7\) is more soluble in water than \(Na_2Cr_2O_7\).
   • Explanation: The solubility of a substance in water depends on several factors, including the ionic radii and lattice energy. Generally, sodium salts such as sodium dichromate \((Na_2Cr_2O_7)\) are more soluble in water than potassium salts due to better solvation of smaller sodium ions compared to larger potassium ions.
   • Conclusion: This statement is incorrect as \(Na_2Cr_2O_7\) is indeed more soluble in water compared to \(K_2Cr_2O_7\).

After analyzing both statements, we conclude that Statement I is correct and II is incorrect.