The reason for adding gypsum to the clinker during the production of cement is .........

The incorrect order of solubility in water is

The alkaline earth metal nitrate that does not crystallise with water molecules is

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 $(A)$?

$A$ substance absorbs $CO_2$ and violently reacts with water. That substance is

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