Although DNA contains both nitrogen base and phosphoric acid, why is DNA only acidic?

DNA is made up of many nucleotides. Two nucleotide chains are joined together by hydrogen bonds to form DNA.

Nucleotides are made up of a deoxyribose sugar, a phosphoric acid (Pi or inorganic phosphate), and a nitrogen base.

Hydrogen bonds are formed with alkali hydrogen and oxygen or nitrogen. And the bases are on the inside of the DNA structure.

But phosphoric acid or phosphates are exposed to the outside. This is why DNA is acidic despite the presence of alkali.

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