Which of the following alkaline earth metals forms complex compounds?

$A$ hydrated colorless solid $(A)$ is water soluble and finds use in medicine as a purgative. When a solution of $(A)$ is treated with ammonium phosphate,a white precipitate is formed. $(A)$ gives a pink mass in the cobalt nitrate cavity test. What is $(A)$?

Which of the following properties is exhibited by group $2$ elements?

The product obtained on fusion of $BaSO_4$ and $Na_2CO_3$ is

The solubility of carbonates of alkaline earth metals decreases down the group due to:

Match column-$I$ with column-$II$ :

Column-$I$	Column-$II$
$(a)$ Calcium	$(p)$ Crimson red
$(b)$ Barium	$(q)$ Brick red
$(c)$ Strontium	$(r)$ Apple green
-	$(s)$ Yellow