The number of moles of KMnO4 reduced by one mole of KI in alkaline medium is
(2) two
As per NCERT, in neutral or faintly alkaline medium permanganate oxidises iodide to iodate:
2MnO4- + I- + H2O 2MnO2 + IO3- + 2OH-
I- (-1) IO3- (+5): 6 electrons lost per I-
MnO4- (+7) MnO2 (+4): 3 electrons gained per MnO4-
Moles of KMnO4 reduced by 1 mol KI = 63 = 2
Answer: (2)
Four successive members of the first row transition elements are listed below with their atomic numbers. Which one of them is expected to have the highest third ionisation enthalpy?
The aqueous solution containing which one of the following ions will be colourless? (Atomic number : Sc = 21, Fe = 26, Ti = 22, Mn = 25)
Among K, Ca, Fe and Zn, the element which can form more than one binary compound with chlorine is
Among the following series of transition metal ions, the one where all metal ions have 3d2 electronic configuration is [At. Nos. Ti = 22, V = 23, Cr = 24, Mn = 25]
Lanthanoids are
Which one of the following characteristics of the transition metals is associated with their catalytic activity?
The basic character of the transition metal monoxides follows the order (Atomic nos. Ti = 22, V = 23, Cr = 24, Fe = 26)
The correct order of ionic radii of Y3+, La3+, Eu3+ and Lu3+ is (Atomic nos. Y = 39, La = 57, Eu = 63, Lu = 71)
General electronic configuration of lanthanides is