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⁺

Which of the following lanthanoids is radioactive?

1. Promethium

2. Europium

3. Plutonium

4. Neptunium

Find the main reason responsible for actinide contraction.
1. Poor shielding by the 5f subshell
2. Extraordinary decrement in Z_eff
3. Both (1) and (2)
4. Strong shielding by the 5f subshell

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