Which of the following oxidation states of manganese exhibits the most powerful oxidizing property?

Which of the following ions can reduce dilute acid to give hydrogen gas?

Discuss the chemical properties of lanthanoids.

Give examples and suggest reasons for the following features of the transition metal chemistry:
$(i)$ The lowest oxide of transition metal is basic,the highest is amphoteric/acidic.
$(ii)$ $A$ transition metal exhibits highest oxidation state in oxides and fluorides.
$(iii)$ The highest oxidation state is exhibited in oxoanions of a metal.

How are transition metals and their oxides used in industrial processes?

What is the general molecular formula of the products obtained on heating lanthanoids $(Ln)$ with sulphur?