The electronegativity of a group 13 element 'E' is same as that of Ge (on Pauling scale and upto one decimal point). The CORRECT statements about E^ 3+ are A. It can act as a reducing agent. B. It can act as an oxidizing agent. C. E^ 3+ is more stable than E^+. D. The standard electrode potential value for E^ 3+ /E is positive. Choose the correct answer from the options given below:
C. B and D Only
The electronegativity of Ge on the Pauling scale is 1.8. In Group 13, the electronegativity values are B (2.0), Al (1.5), Ga (1.6), In (1.7), and Tl (1.8). Thus, the element 'E' is Thallium (Tl). Due to the inert pair effect, the +1 oxidation state is much more stable than the +3 oxidation state for the heavier elements of Group 13, especially Thallium. Therefore, Tl^+ is more stable than Tl^ 3+ . This makes statement C incorrect. Since Tl^ 3+ is relatively unstable, it readily accepts two electrons to form the more stable Tl^+ ion (Tl^ 3+ + 2e^- Tl^+). Because it undergoes reduction easily, Tl^ 3+ acts as a strong oxidizing agent. This makes statement A incorrect and statement B correct. The standard electrode potential for the reduction of Tl^ 3+ to Tl (E^ _ Tl^ 3+ /Tl ) is +1.26 V , which is a positive value. This makes statement D correct. Therefore, only statements B and D are correct.
Related: Chemistry — Classification of Elements and Periodicity in Properties · All PYQ Banks