Question

Halides of Be dissolve in organic solvents while those of Ba do not. Why is it so ?

Answer 1

The halides of beryllium have high ionization enthalpy and so their halides are covalent in nature.

Whereas the halides of barium have low ionization enthalpy and so their halides are ionic in nature.  

We know that covalent compounds are soluble in organic solvents which is not exhibited by ionic compounds.

Hence, the halides of beryllium which are covalent in nature soluble in organic solvents whereas the halides of barium which are ionic in nature and do not dissolve.

Answer 2

Halides of Be are covalent because of high Ionisation Enthalpy of Be while those of Ba are ionic due to low IE of Ba. Hence,Be is dissolve in organic solvents while those of Ba do not.