Which of the following alkaline earth metals does not exhibit colour when heated in a flame?

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 ......

The ion having the highest hydration enthalpy among the given alkaline earth metal ions is:

All of the following substances react with water. Which of the following pairs will produce the same gaseous product upon reaction with water?

All the elements of group $2$ react with water to form metal hydroxide and hydrogen,except the element

Given below are two statements:
Statement $I$: Both $CaCl_2 \cdot 6H_2O$ and $MgCl_2 \cdot 8H_2O$ undergo dehydration on heating.
Statement $II$: $BeO$ is amphoteric whereas the oxides of other elements in the same group are acidic.
In the light of the above statements,choose the correct answer from the options given below: