Question

Given below are two statements : 
Statement I : CrO\( _3 \) is a stronger oxidizing agent than MoO\( _3 \) 
Statement II : Cr(VI) is more stable than Mo(VI) In the light of the above statements, choose the correct answer from the options given below

• A. Statement I is false but Statement II is true
• B. Statement I is true but Statement II is false
• C. Both Statement I and Statement II are true
• D. Both Statement I and Statement II are false

Hint:

Remember the trends in oxidizing power and stability of oxidation states down a group in transition metals. For oxides in higher oxidation states, oxidizing power typically decreases down the group, while the stability of higher oxidation states often increases down the group for heavier elements.

Answer 1

The Correct Option is B

To verify the provided statements, a detailed examination of each is conducted:

Statement I: CrO₃ is a stronger oxidizing agent than MoO₃

This statement is accurate. Chromium trioxide (CrO₃) functions as a potent oxidizing agent. Its high +6 oxidation state facilitates electron acceptance, rendering it an effective electron acceptor. Conversely, Molybdenum trioxide (MoO₃) exhibits weaker oxidizing capabilities. This disparity in oxidizing strength is linked to electronic configurations and periodic trends, with chromium generally demonstrating superior oxidizing potential compared to molybdenum.

Statement II: Cr(VI) is more stable than Mo(VI)

This statement is inaccurate. The stability of oxidation states generally diminishes with increasing atomic number within a group of the periodic table. Chromium in its +6 oxidation state (Cr(VI)) is less stable than Molybdenum in its +6 oxidation state (Mo(VI)). Molybdenum's greater atomic number and lower group position contribute to the enhanced stability of Mo(VI) relative to Cr(VI), which is more susceptible to reduction and disproportionation.

Conclusion:

Following the preceding analysis, Statement I is true, while Statement II is false. Consequently, the correct determination is: Statement I is true but Statement II is false.