The alkaline earth metals $Ba$,$Sr$,$Ca$ and $Mg$ may be arranged in the order of their decreasing first ionisation potential as

Fill in the blanks:
$(1)$ Calcium and beryllium have flame colors of ...... and ....... respectively.
$(2)$ Quantitative analysis of calcium is carried out by ........
$(3)$ Beryllium powder on combustion burns brightly in air and gives ...... and .......
$(4)$ Beryllium hydroxide on dissolving in alkali gives .......

Which hydroxide of the $II^{nd}$ $A$ group metals has the lowest solubility product $(K_{sp})$ value at $25\,^{\circ}C$?

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

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

The correct sequence of increasing melting points of $BeCl_2$,$MgCl_2$,$CaCl_2$,$SrCl_2$,and $BaCl_2$ is: