why dihydrogen is insoluble in water?
Dihydrogen is a non-polar molecule, consisting of two covalently bonded hydrogen atoms. Water, on the other hand is a polar solvent. We know that non-polar solutes are more soluble in non-polar solvents that in polar solvents (like dissolves like principal). Therefore, hydrogen being non-polar is less soluble in water which is a polar solvent with a high dielectric constant.