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-

Basic oxide amongst the following is:

1. CrO

2. Cr₂O₃

3. CrO₃

4. Cr₂O₄

A pair of ions having similar magnetic moments is:

1. Ti³⁺,V³⁺

2. Cr³⁺,Mn²⁺

3. Mn²⁺,Fe³⁺

4. Fe²⁺,Mn²⁺

Lanthanoid which is radioactive is:

1. Promethium

2. Europium

3. Plutonium

4. Neptunium

Actinide contraction is mainly related to:
1. Poor shielding by 5f subshell
2. Extraordinary decrement in Z_eff
3. Both (1) and (2)
4. Strong shielding by 5f subshel

From the following, which is the most basic hydroxide?

1. Ce(OH)₃

2. Lu(OH)₃

3. Yb(OH)₃

4. Tb(OH)₃

Which is colorless in water?

1. Ti³⁺

2. V³⁺

3. Cr³⁺

4. Sc³⁺

CrO₄^2- and MnO₄^- are strong yellow and intense purple  respectively in aqueous solution The darkening of colour is due to

1. charge transfer

2. d-d transition

3. half-filled d-sub shells

4. increasing number of unpaired electron