$BeO$ reacts with $HF$ in the presence of ammonia to give $[A]$,which on thermal decomposition produces $[B]$ and ammonium fluoride. The oxidation state of $Be$ in $[A]$ is $.....$.

An element $P$ has atomic number $56$. What will be the formula of its halide?

Which of the following sulfates is insoluble in water?

Which one of the following alkaline earth metal sulphates has its hydration enthalpy greater than its lattice enthalpy?

$(a)$ Give reactivity of alkaline earth metals towards air,water,dihydrogen and acids.
$(b)$ Explain reducing nature of alkaline earth metals.
$(c)$ Give chemical reaction of alkaline earth metals with liquid ammonia.

What is obtained when quicklime is heated with coke in an electric furnace?