The d- and f- B...

Which of the following is paramagnetic in nature? 

Which of the following reactions are disproportionation reactions?
(I) $$Cu^+ \, \rightarrow \,  Cu^{2+} \, + \, Cu$$
(II) $$\displaystyle 3Mn{ O }{_{4}{^-}} \, + \, 4H^+ \, \rightarrow \,  2Mn{ O }{_{4}^{-}} \, + \, MnO_2 \, + \, 2H_2O$$
(III) $$2KMnO_4 \, \rightarrow \,  K_2MnO_4 \, + \, MnO_2 \, + \, O_2$$
(IV) $$2Mn{ O }{_{4}{^-}} \, + \, 3Mn^{2+} \, + \, 2H_2O \, \rightarrow \, 5MnO_2 \, + 4H{^+}$$

When $$KMnO_4$$ solution is added to oxalic acid solution, the decolourisation is slow in the beginning but becomes instantaneous after some time because:

Which of the following example is not correctly matched?

Some compounds turn dark when exposed to light. They are, therefore, used in photography. A metal used for making such compounds is:

Which of the following is not an actinoid?

Magnetic moment of $${ x }^{ n+ }$$ is $$\sqrt { 24 }$$ B.M. Hence No. of unpaired electron and value of n is _____ respectively.
(Atomic number =26)

Generally transition elements form coloured salts due to the presence of unpaired electrons. Which of the following compounds will be coloured in solid state? 

Metallic radii of some transition elements are given below. Which of these elements will have the highest density?

There are 14 elements in actinoid series. Which of the following elements does not belong to this series?