Bleaching powder is obtained by passing chlorine on

In the given reaction cycle,$X$,$Y$ and $Z$ respectively are:
$CaCl_2 + Na_2CO_3 \rightarrow X + Y$
$X \xrightarrow{Z} CaCl_2$

What happens when:
$(i)$ Magnesium is burnt in air
$(ii)$ Quick lime is heated with silica
$(iii)$ Chlorine reacts with slaked lime
$(iv)$ Calcium nitrate is heated?

$s-$block element which cannot be qualitatively confirmed by the flame test is ..... .

Which property of alkaline earth metals increases with an increase in atomic number?

Heating a solid compound $X$ produces $CO_2$ gas and a residue. Adding water to this residue produces compound $Y$. Passing excess $CO_2$ gas through a solution of $Y$ produces a clear solution $Z$. Boiling $Z$ regenerates compound $X$. What is compound $X$?