Question

Element ‘M’ of group 13 has same electronegativity as Ge. Consider the statements (A) \(M^{3+}\) is good oxidizing agent (B) \(M^{3+}\) is good reducing agent (C) \(E^\circ_{M^{3+}/M} > 0\) (D) \(M^{3+}\) is more stable than \(M^{+}\) Which of the following is correct?

• A. A & D
• B. A & C
• C. B & D
• D. A & D

Answer 1

The Correct Option is B

Let's analyze the question based on the properties of Group 13 elements and their oxidation states:

1. Element 'M' of Group 13 has the same electronegativity as Ge (Germanium). The electronegativity of Ge is approximately the same as that of Gallium (Ga) in Group 13.
2. The possible oxidation states for Group 13 elements are typically +1 and +3. In the case of Gallium, the +3 oxidation state (\(M^{3+}\)) is more prevalent. Let's analyze the statements:

• Statement (A): \(M^{3+}\) is a good oxidizing agent.
• Statement (B): \(M^{3+}\) is a good reducing agent.
• Statement (C): \(E^\circ_{M^{3+}/M} > 0\)
• Statement (D): \(M^{3+}\) is more stable than \(M^{+}\).

1. Analyzing \(M^{3+}\) as an oxidizing agent:

For an ion to be a good oxidizing agent, it should have a tendency to gain electrons and be reduced. Group 13 elements like Ga in the +3 state are indeed good oxidizing agents because they prefer to accept electrons to achieve a stable electron configuration, typically reverting to a more stable lower oxidation state if possible. Therefore, Statement (A) is true.

1. Standard electrode potential \(E^\circ_{M^{3+}/M}\):

The positive value of \(E^\circ\) indicates that the reduction of \(M^{3+}\) to M is feasible, implying that \(M^{3+}\) is a stable form and has a tendency to act as an oxidizing agent. Thus, Statement (C) is correct.

1. Stability of oxidation states:

In Group 13, the stability of the +3 state generally decreases down the group. However, for the lighter members like Ga, the +3 state is still more stable than the +1 state. So, \(\text{Statement (D)}\) holds true in some lighter elements, adding more weight to the possible correctness of C but isn't superior to C.

1. From the analysis, options (A) and (C) stand as correct statements. Hence, the correct answer is "A & C".