since nucleic acis have charged phosphate groups, DNA and RNA contain lots of negative charges. Would you suspect that DNA and RNA are soluble in polar solvent like water?

Answer 1

Yes. The negatively charged phosphate groups would attract the positively charged regions of the molecules making the polar solvent. For example, if the solvent were water, then the H atoms, which carry a partial positive charge, would be attracted to the negative regions of the phosphate group.