When comparing the strengths of hydrochloric acid (HCl) and nitric acid (HNO3), it is generally accepted that nitric acid is the stronger acid.
Both HCl and HNO3 are strong acids, meaning they completely dissociate in water. However, the strength of an acid can also be understood in terms of its ability to donate protons (H+ ions) and the stability of the resulting anion after dissociation.
In the case of HCl, after donating a proton, it forms Cl–, while HNO3, after donating a proton, forms NO3–. The nitrate ion (NO3–) is more stable due to its resonance structures, which delocalize the negative charge across multiple atoms. This stability contributes to nitric acid’s stronger acidic behavior compared to hydrochloric acid.
Additionally, both acids are used in various chemical processes, with nitric acid often referred to as a stronger oxidizing agent as well, further showcasing its strength in chemical reactions.