On heating $ZnCl_2 \cdot 2H_2O$,the compound obtained is

Identify the correct statements from the following:
$I$. $LiF$ is less soluble in water than $NaF$
$II$. Both $LiCl$ and $MgCl_2$ are insoluble in ethanol
$III$. Both $Li$ and $Mg$ form nitrides
$IV$. $Na_2CO_3$ gives $CO_2$ on heating

Which of the given orders is not correct?

Match Column-$I$ with Column-$II$ :

Column-$I$	Column-$II$
$(a)$ $NaOH$	$(p)$ Silvine
$(b)$ $Na_2CO_3$	$(q)$ As cooling agent in nuclear reactor
$(c)$ Liquid $Na$	$(r)$ Detergent soap
$(d)$ Potassium	$(s)$ In purification of Bauxite

What is the chemical formula for green vitriol?

Which compound on heating produces a coloured metal oxide finally?