CBSE Class 12 Chemistry — The d- and f-Block Elements

Which of the following is not a transition metal?

Assertion (A): Actinoids show wide range of oxidation states. Reason (R): Actinoids are radioactive in nature.

(a) (i) From the given data of E° values, answer the following questions: (3 + 2) $E^\circ(M^{2+}/M)$ values (V): $V = -1.18, Cr = -0.91, Mn = -1.18, Fe = -0.44, Co = -0.28, Ni = -0.25, Cu = +0.34$ (I) Why $E^\circ(M^{2+}/M)$ show irregular trend in the above values? (II) Why is $E^\circ(Cu^{2+}/Cu)$ value exceptionally positive? (III) Why $E^\circ(Mn^{2+}/Mn)$ value is highly negative? (ii) Write the ionic equations for the oxidising action of potassium permanganate for its reaction with $I^-$ in both acidic and alkaline solutions. OR (b) Answer the following questions: (1 + 1 + 1 + 2) (i) Name a member of the lanthanoid series (I) which exhibits +4 oxidation state (II) which exhibits +2 oxidation state. (ii) Why transition metals act as good catalyst? (iii) Why Cr has higher melting point than Mn? (iv) What happens when acidic solution of potassium permanganate is allowed to stand for sometime? Give the equation involved. What is this type of reaction called?