DNA is acidic in nature due to

DNA is a polymer of nucleotides which are made up of sugar, a nitrogenous base and phosphate moiety. DNA has four bases; two purines and two pyrimidines which are alkaline in nature; options B and D are incorrect. The two purines are namely adenine and guanine and two pyrimidines are cytosine, thymine. The nucleotide units of DNA contain 2? deoxy-D-ribose sugar which is bonded to bases by glycosyl linkage and to phosphate by esterification that renders it non-acidic; option A is incorrect. The phosphate group in the DNA molecule is present as a phosphoric acid molecule which can donate two protons and is negatively charged (as the remaining proton is lost easily), thereby imparting acidic nature to DNA.