Which from the following is the general formula of the compound obtained when lanthanoid $(Ln)$ reacts with carbon at elevated temperature?

Which of the following is incorrect about $K_{2}Cr_{2}O_{7}$?

Which one of the following,when dissolved in water,gives a coloured solution in a nitrogen atmosphere?

Give the formulas of the oxocations of the $3d$ series metals.

Manganese steel is used for making railway tracks because

Give the preparation of potassium dichromate and state its uses.
Give the structures of chromate and dichromate ions. How can chromates and dichromates be interconverted?
Give the chemical reactions showing the oxidizing nature of potassium dichromate.