The complex formation tendency of alkaline earth metals decreases down the group because

$Be(OH)_2$ reacts with $Sr(OH)_2$ to yield an ionic salt. Choose the incorrect option related to this reaction from the following:

The alkaline earth metals $Ba$,$Sr$,$Ca$ and $Mg$ may be arranged in the order of their decreasing first ionisation potential as

The property of the alkaline earth metals that increases with their atomic number is

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 $X$?

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