Question

How does the oxyacid strength of the halogens vary as the number of oxygens in the formula increases?

Short answer

The oxyacid strength of halogens increases as the number of oxygens in the formula increases. This is due to the increased electron-withdrawing effect caused by the presence of multiple oxygen atoms, which weakens the bond between the hydrogen atom and the oxygen atom, making it easier to release the hydrogen ion as a proton and enhancing the acidity of the molecule.

Step-by-step solution

Understanding Oxyacids of Halogens

Oxyacids are a class of compounds that contain an acidic hydrogen atom bonded to an oxygen atom. Oxyacids of halogens are compounds in which the halogen atoms (such as fluorine, chlorine, bromine, and iodine) are attached to these oxygen atoms. These compounds have the general formula HOXO_n, where X represents the halogen and n represents the number of oxygen atoms. Examples include hypochlorous acid (HOCl), chlorous acid (HClO_2), chloric acid (HClO_3), and perchloric acid (HClO_4).

Comparing Oxyacid Strengths

To understand the variation in oxyacid strength as the number of oxygens in the formula increases, we will analyze the relationship between the presence of oxygens and the strength of the bond between the hydrogen atom and the oxygen atom. An oxyacid is considered stronger when this bond is weaker, and easier to break, thus allowing the hydrogen ion to be released as a proton (H^+).

The Effect of Increasing the Number of Oxygens

As the number of oxygen atoms in the oxyacid molecule increases, there is an increase in the electron-withdrawing effect. The oxygen atoms are more electronegative, which means they have a higher affinity for electrons and will draw the bonding electrons away from the hydrogen atom. This causes a decrease in the bond strength between the hydrogen and the oxygen atoms, making the compound more acidic.

Understanding the Relationship

As a result, we can establish a relationship between the number of oxygens in the oxyacid formula and the acidity of the compound: the more oxygens, the greater the acidity. This is because the presence of multiple oxygen atoms enhances the electron-withdrawing effect. In summary, oxyacid strength of halogens increases as the number of oxygens in the formula increases, due to the increased electron-withdrawing effect. This effect weakens the bond between the hydrogen atom and the oxygen atom, making it easier to release the hydrogen ion as a proton and enhancing the acidity of the molecule.