List of top Chemistry Questions on General Properties of the Transition Elements (d-Block) asked in CBSE Class XII

In aqueous acidified solution, CrO$_4^{2-}$ ion converts to which of the following ?

Answer the following: \[ (a)(i)\;\text{Describe giving reason which one of the following pairs has the property indicated:} \] \[ (I)\;Fe\text{ or }Cu-\text{higher melting point} \] \[ (II)\;Ti^{3+}\text{ or }Sc^{3+}-\text{coloured in aqueous solution} \] \[ (III)\;Cr\text{ or }Zn-\text{higher third ionisation enthalpy} \] \[ (a)(ii)\;\text{Write the ionic equations for the oxidizing action of }MnO_4^-\text{ in acidic medium with:} \] \[ (I)\;Fe^{2+}\text{ ion} \] \[ (II)\;I^-\text{ ion} \]

From the given data of E° values, answer the following questions:
E°_M²⁺/M (V): Cr = –1.18, Mn = –1.18, Fe = –0.44, Co = –0.28, Ni = –0.25, Cu = +0.34
(I) Why does E°_M²⁺/M show an irregular trend in the above values?
(II) Why is the E°_Cu²⁺/Cu value exceptionally positive?
(III) Why is the E°_Mn²⁺/Mn value highly negative?

Why does Cr have a higher melting point than Mn?

From the given data of standard electrode potential E°_M²⁺/M values (in volts): Cr = -1.18, Mn = -1.18, Fe = -0.44, Co = -0.28, Ni = -0.25, Cu = +0.34, answer the following: (I) Why does E°_M²⁺/M show an irregular trend in the above values? (II) Why is E°_Cu²⁺/Cu value exceptionally positive? (III) Why is E°_Mn²⁺/Mn value highly negative?

Why do transition metals act as good catalysts?