Holme's signals can be obtained by using

The initial setting of cement is primarily due to which of the following?

Identify the elements of alkali metals and alkaline earth metals respectively having the highest $1^{st}$ ionization enthalpy.

Match List-$I$ with List-$II$ :

List-$I$ (Elements)	List-$II$ (Properties)
$(a)$ $Ba$	$(i)$ Organic solvent soluble compounds
$(b)$ $Ca$	$(ii)$ Outer electronic configuration $6s^2$
$(c)$ $Li$	$(iii)$ Oxalate insoluble in water
$(d)$ $Na$	$(iv)$ Formation of very strong monoacidic base

Choose the correct answer from the options given below :

Which of the following substances is used as a fertilizer?

Identify the correct statements from the following:
$I$. $LiF$ is less soluble in water than $NaF$
$II$. Both $LiCl$ and $MgCl_2$ are insoluble in ethanol
$III$. Both $Li$ and $Mg$ form nitrides
$IV$. $Na_2CO_3$ gives $CO_2$ on heating