The use of Plaster of Paris is ..........

On heating,which of the following releases $CO_2$ most easily?

Which one of the alkaline earth metals shows some anomalous behaviour and has the same electronegativity as aluminium?

Assertion $(A)$: $Be$ and $Mg$ do not impart any colour to the flame.
Reason $(R)$: The electrons in them are too strongly bound to get excited by the energy of the flame.
The correct option among the following is:

Which element from the following is used for cancer treatment?

$Ba$,$Ca$,and $Sr$ form halide hydrates. Their formulas are $BaCl_2 \cdot x H_2 O$,$CaCl_2 \cdot y H_2 O$,and $SrCl_2 \cdot z H_2 O$. The values of $x$,$y$,and $z$ respectively are: