Which one is the weakest acid
A) hno3
B) hclo3
C) h2so4
D) hbr
And why not another's?
Detail answer, please.

To determine which of the given acids is the weakest, we need to consider their strengths based on their dissociation in water. The acids listed are nitric acid (HNO3), chloric acid (HClO3), sulfuric acid (H2SO4), and hydrobromic acid (HBr). Each of these acids has a different degree of ionization, which directly affects their acidity.

Understanding Acid Strength

Acid strength is often measured by the extent to which an acid donates protons (H+) in a solution. Strong acids completely dissociate in water, while weak acids only partially dissociate. The more completely an acid dissociates, the stronger it is considered.

Analyzing Each Acid

• Nitric Acid (HNO3): This is a strong acid that completely dissociates in water, releasing one proton (H+) and forming nitrate ions (NO3-).
• Chloric Acid (HClO3): Similar to nitric acid, chloric acid is also a strong acid and fully dissociates in solution, producing H+ and ClO3- ions.
• Sulfuric Acid (H2SO4): This is one of the strongest acids known. The first dissociation is complete, yielding H+ and HSO4- ions. The second dissociation (HSO4- to SO4^2-) is also strong but not complete, making it a diprotic acid.
• Hydrobromic Acid (HBr): Like HCl and HNO3, HBr is a strong acid that fully dissociates in water, producing H+ and Br- ions.

Identifying the Weakest Acid

Among the options provided, all the acids listed are classified as strong acids, but the one that is considered the weakest in this group is sulfuric acid (H2SO4) when comparing the second dissociation step. While the first dissociation is complete, the second step is not, which means it does not fully dissociate in solution.

Conclusion

In summary, while HNO3, HClO3, and HBr are strong acids that completely dissociate, H2SO4 is the weakest in this context due to its partial dissociation in the second step. Therefore, the answer to your question is D) H2SO4, as it is the weakest acid among the options provided, primarily due to its incomplete dissociation in the second step.