In the alkaline earth metals,the element forming predominantly covalent compounds is

Equimolar solutions of the following were prepared in water separately. Which one of the solutions will record the highest $pH$?

What is the chemical formula for Plaster of Paris?

From which of the following reactions can anhydrous $MgCl_2$ be prepared?

What are the products formed in sequence when excess of $CO_{2}$ is passed in slaked lime?

Heating compound $(A)$ produces a colorless gas and a residue $(B)$ which dissolves in water. Passing excess $CO_2$ gas through the aqueous solution of $(B)$ yields compound $(C)$,which is obtained in solid state. Gently heating compound $(C)$ gives back the white solid $(A)$. What is compound $(A)$?