Which of the following element does not show the variable oxidation state?

1. Fe

2. Mn

3. Cu

4. Zn

With F highest stable oxidation state of Mn is

1. +6

2. +4

3. +7

4. +3

Cr₂O₇^2-+X$\stackrel{{\mathrm{H}}^{+}}{\to }$Cr³⁺+H₂O + oxidized product of X. X in the above reaction cannot be

1. C₂O₄^2-

2. Fe²⁺

3. SO₄^2-

4. S^2-

A pair of ions having similar magnetic moments is:

1. Ti³⁺,V³⁺

2. Cr³⁺,Mn²⁺

3. Mn²⁺,Fe³⁺

4. Fe²⁺,Mn²⁺

The main reason for a larger number of oxidation states exhibited by the actinoids than the corresponding lanthanoids is

1. The lesser energy difference between 5f and 6d orbitals than 4f and 5d orbitals

2. Larger atomic size of actinoids than the lanthanoids

3. More energy difference between 5f and 6d orbitals than between 4f and 5d orbitals

4. Greater reactive nature of the actinoids than the lanthanoids

In the dichromate ion Cr₂O₇^2-,

1. 4 Cr-O bonds are equivalent

2. 6 Cr-O bonds are equivalent

3. All Cr-O bonds are equivalent

4. None of Cr-O bonds are equivalent

The electronic configuration of a transition element X in +3 Oxidation state is [Ar]3d⁵.

The atomic number of X is :

1. 25

2. 26

3. 27

4. 24

Magnetic moment of K₃[Fe(CN)₅(H₂O)] is

1. 0

2. 4.92

3. 3.87

4. 2.83

The colour of KMnO₄ is due to  :

1. d-d transition

2. Charge transfer spectra

3. Polarisation of ion

4. p-d transition

Which element among the following has the highest melting point?

1. Cr

2. Fe

3. Cu

4. Mo