KCET2026Chemistryd and f Block Elements
Which of the following will not act as an oxidising agent?
Options
- ACrO ₃
- BMoO ₃
- CCrO ₄²⁻
- DCr ₂ O ₇²⁻
Correct answer
B. MoO ₃
Step-by-step solution
In Group 6 elements (Cr, Mo, W), the stability of the higher oxidation state (+6) increases down the group. Therefore, Mo(VI) and W(VI) are much more stable than Cr(VI). Compounds of Cr(VI) such as CrO ₃ , CrO ₄²⁻ , and Cr ₂ O ₇²⁻ are strong oxidising agents because Cr(VI) can easily be reduced to the more stable Cr(III) state. On the other hand, Mo(VI) in MoO ₃ is highly stable and does not undergo reduction easily. Thus, MoO ₃ does not act as an oxidising agent. Answer: MoO ₃