goosegirl

Hi all! I'm having trouble visualizing a question that asks to compare double-stranded DNA in a solution of PH 7 with a low salt concentration or in water with no ions. In which solution would DNA have a lower melting temperature? I know that DNA is a polar molecule that is negatively charged. Would the ions in the first solution neutralize the DNA and allow it to more easily dissociate (lower melting temperature) than the DNA in the water that wouldn't neutralize the molecule? Or does it have to do more with which one allows it to more easily hydrogen bond?