Fill in the blanks:
$(a)$ The unit of magnetic moment is ......... .
$(b)$ $Mn^{2+}$ has .......... color.
$(c)$ $Fe_3H$ is a ............. type of compound.

Potassium permanganate on heating at $513 \ K$ gives a product which is :

The conversion of pig iron to steel frequently requires the addition of
$(I)$ oxygen or iron oxide
$(II)$ transition elements
$(III)$ inner transition elements
$(IV)$ silica

Which of the following compounds shows colour due to $d-d$ transition?

Describe the oxidising action of potassium dichromate and write the ionic equations for its reaction with:
$(i)$ iodide
$(ii)$ iron $(II)$ solution and
$(iii)$ $H_{2}S$

When a mixture of manganese dioxide,potassium hydroxide and potassium chlorate is fused,the product obtained is