Answer the question on the basis of passage given below:

All transition elements display typical metallic properties like high melting point, boiling point, tensile strength, high malleability and ductility, luster, etc. Their metallic character increases down the group and elements of 4d and 5d series exhibit higher metallic characters. They show variable oxidation states and forms a number of coloured compounds due to the presence of unpaired electrons which shows d-d transitions and makes them paramagnetic.

The two strongest oxidising agents among the oxides will be -

A. $MoO_3$
B. $CrO_3$
C. $Mn_2O_7$
D. $WO_3$
E. $VO_2$

Choose the correct answer from the options given below:

B and C only

The correct answer is Option (4) → B and C only.

Oxidizing agents are substances that can accept electrons from other compounds, causing them to be oxidized while the oxidizing agent itself gets reduced. The strength of an oxidizing agent depends on the ability of its central atom to attain a lower oxidation state by accepting electrons.

In the given oxides, the central atoms are in high oxidation states, and their ability to act as strong oxidizing agents is directly linked to how easily they can be reduced (gain electrons). Let's analyze each oxide:

A. MoO₃ (Molybdenum trioxide):

Oxidation state of Molybdenum: +6

While molybdenum is in a high oxidation state in MoO₃, it is not as strong an oxidizing agent as CrO₃ or Mn₂O₇. Molybdenum is more stable in the +6 oxidation state compared to chromium and manganese in their respective oxides.

Moderate Oxidizing Agent: MoO₃ can still act as an oxidizing agent, but it is not as strong as CrO₃ or Mn₂O₇.

B. CrO₃ (Chromium trioxide):

Oxidation state of Chromium: +6

Chromium in the +6 oxidation state is highly unstable and has a great tendency to be reduced to lower oxidation states like +3. This makes CrO₃ a very strong oxidizing agent. It is commonly used in laboratory settings for oxidative reactions (e.g., in organic chemistry, it is used to oxidize alcohols to aldehydes or ketones).

Strong Oxidizing Agent: Chromium trioxide is known for its strong oxidizing capabilities because of the high oxidation state of chromium (+6). It readily accepts electrons, reducing itself and oxidizing other substances.

C. Mn₂O₇ (Manganese heptoxide):

Oxidation state of Manganese: +7

Manganese in the +7 oxidation state is extremely unstable and has a strong tendency to gain electrons to be reduced to lower oxidation states like +2 or +4. Mn₂O₇ is an exceptionally strong oxidizing agent, and it can cause explosive reactions with organic materials due to its vigorous oxidation potential.

Strong Oxidizing Agent: Manganese heptoxide is among the strongest oxidizing agents because manganese in the +7 state is highly reactive and eager to accept electrons. It can oxidize even tough-to-oxidize compounds, including organic substances, and is often used in very controlled settings

D. WO₃ (Tungsten trioxide):

Oxidation state of Tungsten: +6

Tungsten in WO₃ is relatively stable in the +6 oxidation state, similar to molybdenum in MoO₃. Although WO₃ can act as an oxidizing agent, it is much less reactive compared to CrO₃ and Mn₂O₇.

Weak Oxidizing Agent: Due to tungsten’s relatively stable oxidation state, WO₃ is not a strong oxidizing agent.

E. VO₂ (Vanadium dioxide):

Oxidation state of Vanadium: +4

Vanadium in VO₂ is in a lower oxidation state (+4). This oxide does not have strong oxidizing power because vanadium is more stable in this oxidation state. VO₂ can undergo further oxidation but does not act as a strong oxidizing agent.

Weak Oxidizing Agent: VO₂ is not considered a strong oxidizing agent because vanadium is not in its highest oxidation state (+5), where it would exhibit stronger oxidizing behavior.

Conclusion:

CrO₃ and Mn₂O₇ are the strongest oxidizing agents among the given oxides because their central atoms (chromium and manganese) are in high and unstable oxidation states (+6 and +7, respectively).

These oxides are more prone to gaining electrons, making them strong oxidizing agents compared to MoO₃, WO₃, and VO₂, which are either more stable or in lower oxidation states.

Thus, the correct answer is B and C only (CrO₃ and Mn₂O₇).