Complete hydrolysis of DNA does not yield
Answer & explanation
Correct answer: option 4
The correct answer is Option (4) → Secondary alcohol
DNA is a polymer of nucleotides, each made of a pentose sugar (β-D-2-deoxyribose), a nitrogenous base (adenine, guanine, cytosine or thymine) and a phosphate group. Complete hydrolysis gives back only these three kinds of building blocks.
Option (1) Phosphoric acid — A product of complete hydrolysis of DNA. The phosphate groups of the phosphodiester links are released as phosphoric acid.
Option (2) Pentose sugar — A product of complete hydrolysis of DNA. The sugar unit of DNA is the pentose β-D-2-deoxyribose.
Option (3) Nitrogen-containing compound — A product of complete hydrolysis of DNA. The four bases A, G, C and T are nitrogen-containing heterocycles.
Option (4) Secondary alcohol — Not a product of complete hydrolysis of DNA. None of the three building blocks is a secondary alcohol, so it is not formed.
NCERT (2026-27 edition):
Chemical Composition of Nucleic Acids
