DNA is an interesting molecule in that it has both acidic and alkaline components. It consists of an acidic phosphate group, an alkaline nitrogenous base and a sugar group. However, because the nitrogenous bases of DNA are oriented inward on the ladder and the sugar-phosphate backbones of each chain is on the outside, the acidic components of the molecule dominate, hence the name deoxyribonucleic acid.

While the exact pH value of DNA is not explicitly reported anywhere, there is substantial evidence to support that the DNA duplex is quite stable at pH 5 to 9. If the pH becomes to acidic or alkaline, DNA molecules are susceptible to DNA melting, depurination and denaturation.