Which one of the following pairs of elements is called 'chemical twins' because of their very similar chemical properties ?
Mn and W
Mo and Tc
Fe and Re
Hf and Zr
Potassium permanganate acts as an oxidant in alkaline and acidic media. The final products formed from KMnO4 in the two conditions are respectively
MnO2- and Mn3+
Mn3+ and Mn2+
Mn2+ and Mn3+
MnO2 and Mn2+
The catalytic activity of the transition metals and their compounds is described to :
their chemical reactivity
their magnetic behaviour
their unfilled d-orbitals
their ability to adopt multiple oxidation states and their complexing ability
The magnetic moment µ, of transition metals is related to the number of unpaired electrons, n as:
μ =
μ = n (n + 2)2
μ = n2 (n + 2)
μ = n/ (n + 2)
The compound ZnFe2O4 is:
a normal spinel compound
a inverse spinel compound
interstitial compound
covalent compound
A.
a normal spinel compound
The compound ZnFe2O4 is a normal spine compound.
Ferrous ion charges to X ion, on reacting with acidified hydrogen peroxide. The number of d-electrons present in X and its magnetic moment (in BM) are, respectively :
6 and 6.93
5 and 5.92
5 and 4.9
4 and 5.92
A complex compound of Co3+ with molecular formula CoClx. yNH, gives a total of 3 ions when dissolved in water. How many Cl- ions satisfy both primary and secondary valencies is this complex?
3
1
4
zero
Identify the correct order in which the covalent radius of the following elements increases
(I)Ti, (II) Ca, (III) Sc
(I), (II), (III)
(III), (II), (I)
(II), (I), (III)
(I), (III), (I)
Which of the following pair of transition metal ions, have the same calculated values of magnetic moment ?
Ti2+ and V2+
Fe2+ and Cu2+
Cr2+ and Fe2+
Co2+ and Ti2+