Oxidation states and standard electrode potentials

27 questions on Oxidation states and standard electrode potentials from the d- and f-Block Elements chapter: 5 NEET level, 11 JEE Main, 11 JEE Advanced. Each one opens with its answer and solution.

• The maximum oxidation state shown by manganese in its compounds is NEET level
• The oxidation state of chromium in K2Cr2O7 is NEET level
• Among the following 3d elements, the one that shows only a single non-zero oxidation state in its compounds is NEET level
• The oxidation state of manganese in the green compound K2MnO4 is NEET level
• Among the following couples, the only one with a positive standard reduction potential is NEET level
• Given E deg(Cu^+/Cu) = +0.52 V and E deg(Cu^2+/Cu^+) = +0.16 V, which statement about Cu^+ in aqueous solution at 298 K (standard conditions) is correct? JEE Main level
• Among the following aqueous ions, the one with the highest spin-only magnetic moment is JEE Main level
• Assertion (A): Mn^3+ is a much stronger oxidising agent than Fe^3+ in aqueous solution. Reason (R): Reduction of Mn^3+ gives the stable half-filled d^5 ion Mn^2... JEE Main level
• Match the species in Column I with the oxidation state of the metal in Column II. Column I: (P) VO2^+ (Q) MnO4^2- (R) [Fe(CN)6]^3- (S) Ni(CO)4 Column II: (1) 0 ... JEE Main level
• For the reaction 2Fe^3+ + Sn^2+ -> 2Fe^2+ + Sn^4+ at 298 K, use E deg(Fe^3+/Fe^2+) = +0.77 V, E deg(Sn^4+/Sn^2+) = +0.15 V and F = 96500 C mol^-1. Delta G deg f... JEE Main level
• The positive value of E deg(Cu^2+/Cu), unlike the other 3d metals of the same row, is best explained by JEE Main level
• The third ionisation enthalpy of Mn is distinctly higher than that of Fe because JEE Main level
• In acidic solution, potassium manganate (K2MnO4) undergoes disproportionation: 3MnO4^2- + 4H^+ -> 2MnO4^- + MnO2 + 2H2O. The mole ratio of MnO4^- formed to MnO2... JEE Main level
• Which one of the following hydrated ions is colourless in aqueous solution? JEE Main level
• Given E deg(Br2/Br^-) = +1.09 V, E deg(I2/I^-) = +0.54 V, E deg(Sn^4+/Sn^2+) = +0.15 V, E deg(Cu^2+/Cu) = +0.34 V and E deg(Fe^3+/Fe^2+) = +0.77 V, which specie... JEE Main level
• Given E deg(Cr^3+/Cr^2+) = -0.41 V and E deg(Cr^2+/Cr) = -0.91 V, calculate E deg(Cr^3+/Cr) in volts, to two decimal places. JEE Main level
• A high-spin aqueous M^2+ ion of a 3d metal has a spin-only magnetic moment of about 4.90 BM, and E deg(M^3+/M^2+) = -0.41 V. The spin-only magnetic moment (in B... JEE Advanced level
• The following data (in kJ mol^-1) are given: for Zn, Delta_aH = 130, Delta_iH_1 + Delta_iH_2 = 2640, Delta_hydH(Zn^2+) = -2046; for Cu, Delta_aH = 338, Delta_iH... JEE Advanced level
• Use E deg(MnO4^-/Mn^2+) = +1.51 V and E deg(Fe^3+/Fe^2+) = +0.77 V (acidic medium, 2.303RT/F = 0.0591 V at 298 K). For the balanced reaction of MnO4^- with Fe^2... JEE Advanced level
• Take E deg(Mn^3+/Mn^2+) = +1.57 V and E deg(MnO2/Mn^3+) = +0.95 V (acidic solution, F = 96500 C mol^-1). For 2Mn^3+ + 2H2O -> Mn^2+ + MnO2 + 4H^+ as written, De... JEE Advanced level
• Arrange the following ions in increasing order of spin-only magnetic moment (high-spin where applicable): Mn^3+, V^3+, Cu^2+, Co^2+. JEE Advanced level
• Excess-free zinc is added to a solution containing 0.20 mol of Fe^3+ until all iron is deposited as the metal. Use E deg(Zn^2+/Zn) = -0.76 V, E deg(Fe^2+/Fe) = ... JEE Advanced level
• Select the correct statements about oxidation states in the following species. JEE Advanced level
• Standard reduction potentials are: Cr^3+/Cr^2+ = -0.41 V, Fe^3+/Fe^2+ = +0.77 V, Mn^3+/Mn^2+ = +1.57 V, Co^3+/Co^2+ = +1.97 V, Cu^2+/Cu = +0.34 V. Which of the ... JEE Advanced level
• Select the correct statements about the following aqueous ions (spin-only values). JEE Advanced level
• In aqueous solution, which of the following species are unstable towards disproportionation under the conditions stated (acidic or neutral medium as appropriate... JEE Advanced level
• Which of the following statements about the stability of oxidation states in aqueous solution are correct? JEE Advanced level