Among the sulphates of alkaline earth metals,the solubilities of $BeSO_4$ and $MgSO_4$ in water,respectively,are

Which of the following is a pair of amphoteric hydroxides?

Fill in the blanks:
$(1)$ Calcium oxide is commonly known as .......
$(2)$ $A$ suspension of calcium hydroxide in water is known as ....
$(3)$ The common name of calcium hydroxide is .......
$(4)$ The general name of calcium sulphate hemihydrate is ......

Plaster of Paris is hardened by

What is dead burnt plaster?

Which property of the alkaline earth metals increases with their atomic number?