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Why is RNA less chemically stable than DNA?

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Diagram of a DNA polynucleotide chain showing linked deoxyribose sugars, phosphate groups, and nitrogenous bases (adenine, guanine, cytosine, thymine), with an inset comparing ribose and uracil in RNA. — Nucleic acid A portion of the polynucleotide chain of deoxyribonucleic acid (DNA), with an inset showing the corresponding pentose sugar and pyrimidine base in ribonucleic acid (RNA).

RNA is less chemically stable than DNA primarily due to the presence of a reactive hydroxyl (-OH) group attached to the second carbon atom of the ribose sugar in the RNA molecule.12

In contrast, DNA contains deoxyribose, which lacks this reactive hydroxyl group at the same position. The presence of the 2′-hydroxyl group in RNA makes the molecule prone to hydrolysis, particularly in the presence of alkali, which leads to the rapid cleavage of the phosphodiester bonds that link the ribose and phosphate groups. This chemical lability is considered a key reason why DNA evolved to be the preferred, more stable carrier of genetic information in most organisms, whereas RNA is more reactive and often subject to constant synthesis and degradation within the cell.21