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

Concept: Electronegativity helps identify the element in the periodic table. The Pauling electronegativity of Ge is approximately \(1.8\).
Step 1: Identify the element \(M\) In group 13, the element having electronegativity close to \(1.8\) is \(\text{Tl}\) (Thallium). Thus, \[ M = Tl \]
Step 2: Nature of oxidation states Thallium commonly shows \(+1\) and \(+3\) oxidation states. Due to inert pair effect, the \(+1\) oxidation state is more stable than \(+3\). Hence, \[ Tl^{+} \text{ is more stable than } Tl^{3+} \]
Step 3: Check oxidizing behaviour Since \(Tl^{3+}\) easily gains electrons to convert into \(Tl^{+}\), \[ Tl^{3+} + 2e^- \rightarrow Tl^{+} \] Thus \(Tl^{3+}\) acts as a good oxidizing agent. Statement (A) is correct.
Step 4: Standard reduction potential The standard reduction potential for \[ Tl^{3+} + 3e^- \rightarrow Tl \] is positive: \[ E^\circ_{Tl^{3+}/Tl} = +1.26\,V \] Thus, \[ E^\circ_{M^{3+}/M} > 0 \] Statement (C) is correct.
Step 5: Check remaining statements (B) \(M^{3+}\) is good reducing agent → False (D) \(M^{3+}\) more stable than \(M^{+}\) → False Thus correct statements are: \[ \boxed{A \text{ and } C} \]