Maximum covalent character is associated with the compound:

How would you explain the following observations?
$(i)$ $BeO$ is almost insoluble but $BeSO_4$ is soluble in water.
$(ii)$ $BaO$ is soluble but $BaSO_4$ is insoluble in water.
$(iii)$ $LiI$ is more soluble than $KI$ in ethanol.

Why is $LiF$ almost insoluble in water whereas $LiCl$ soluble not only in water but also in acetone?

Which of the following statements are correct?
$(A)$ Both $LiCl$ and $MgCl_2$ are soluble in ethanol.
$(B)$ The oxides $Li_2O$ and $MgO$ combine with excess of oxygen to give superoxide.
$(C)$ $LiF$ is less soluble in water than other alkali metal fluorides.
$(D)$ $Li_2O$ is more soluble in water than other alkali metal oxides.
Choose the most appropriate answer from the options given below.

Polarisability of halide ions increases in the order:

Amongst the following species,maximum covalent character is exhibited by