Which element from the following forms a chlorophyll complex?

Which of the following has the highest solubility product?

Which among the following alkali metal chlorides crystallises in the form of a hydrate?

Compound $A$ reacts with $NH_4Cl$ and forms a compound $B$. Compound $B$ reacts with $H_2O$ and excess of $CO_2$ to form compound $C$,which on reaction with saturated $NaCl$ solution forms sodium hydrogen carbonate. Compounds $A, B$ and $C$ are respectively:

Mercury is transported in containers made of

What are the common physical and chemical features of alkali metals?