Calcium cyanamide on treatment with steam under pressure gives ammonia and

Which of the following has the highest calorific value?

Identify the correct statements from the following:
$(I)$ The formula of Calgon is $Na_6(PO_3)_6$.
$(II)$ Exhausted permutit is regenerated by aqueous $KCl$ solution.
$(III)$ Calcium stearate is soluble in water.
$(IV)$ In ice crystals,each oxygen is surrounded by four oxygen atoms.

What is Carbogen?

Match the correct option from Column $-A$ and Column $-B$.

Column $-A$	Column $-B$
$(1)$. $VH$	$(a)$. Ionic hydride
$(2)$. $HF$	$(b)$. Metallic hydride
$(3)$. $MgH_2$	$(c)$. Electron precise hydride
$(4)$. $B_2H_6$	$(d)$. Molecular hydride

The oxidation states shown by hydrogen are