Question

\(\mathrm{H}_{2} \mathrm{O}_{2}\) exists as \(\ldots . .\) in alkaline medium (a) \(\mathrm{HO}_{2}^{\oplus}\) (b) \(\mathrm{H}_{2} \mathrm{O}^{\oplus}\) (c) \(\mathrm{HO}_{2}^{-}\) (d) \(\mathrm{O}_{2}^{2-}\)

Short answer

In an alkaline medium, \(\mathrm{H}_{2} \mathrm{O}_{2}\) exists as \(\mathrm{HO}_{2}^{-}\).

Step-by-step solution

Understanding the Chemical Environment

Hydrogen peroxide, \(\mathrm{H}_{2} \mathrm{O}_{2}\), is in an alkaline medium. In alkaline solutions, substances may dissociate to form ions, depending on the nature of the substance and the pH levels present.

Analyzing Potential Ions Formed

In an alkaline medium, which is basic in nature, hydrogen peroxide can dissociate to form ions that are more stable in such an environment.

Evaluating the Stability of Given Ions

The possible ions in an alkaline medium from \(\mathrm{H}_{2} \mathrm{O}_{2}\) could be \(\mathrm{HO}_{2}^{-}\), \(\mathrm{H}_{2} \mathrm{O}^{\oplus}\), \(\mathrm{HO}_{2}^{\oplus}\), and \(\mathrm{O}_{2}^{2-}\). In a basic environment, a negatively charged ion like \(\mathrm{HO}_{2}^{-}\) is more stable compared to positively charged ions.

Selecting the Most Likely Ion Formed

Among the options, \(\mathrm{HO}_{2}^{-}\) is the ion that hydrogen peroxide forms in an alkaline medium. The formation of \(\mathrm{HO}_{2}^{-}\) is due to the release of a hydrogen ion \(\mathrm{H}^{+}\), which is facilitated by the presence of the hydroxide ions (\(\mathrm{OH}^{-}\)) in alkaline solutions.

Key concepts

Hydrogen Peroxide Dissociation

Hydrogen peroxide, noted for its formula \(\mathrm{H}_2 \mathrm{O}_2\), is a compound that readily dissociates in various chemical environments. This process involves breaking down into different ions or simpler molecules. In alkaline media, where the \(\text{pH}\) is above 7, dissociation tends to produce ions that complement the basic conditions.
It's important to recognize that in such an environment, ions with negative charges are more prevalent. This occurs because the basic medium, characterized by ample hydroxide ions (\(\mathrm{OH}^-\)), encourages the release of hydrogen ions (\(\mathrm{H}^+\)) from compounds like hydrogen peroxide.
Thus, the dissociation allows \(\mathrm{H}_2 \mathrm{O}_2\) to transform into more stable ion species under these conditions, enhancing certain chemical reactions that rely on such ionic forms.

Ions in Alkaline Solutions

In alkaline environments, reactions often involve ions due to the presence of abundant hydroxide ions (\(\mathrm{OH}^-\)). When substances like hydrogen peroxide dissolve in an alkaline solution, they might dissociate into ions that harmonize with the negative charge environment.
To understand this clearly, consider the following points:

• Ions form as substances react with \(\mathrm{OH}^-\) ions present in the solution.
• Negatively charged ions, such as \(\mathrm{HO}_2^-\), become prevalent because of their compatibility with the anionic environment.
• This compatibility also depends on the stability of such ions in terms of energy levels, which favor negatively over positively charged ions in basic settings.

The interaction between these ions and certain chemicals dictates numerous chemical processes, making the knowledge of ion behavior vital in alkaline medium analysis.

Stability of Ions

In chemistry, the stability of ions is a crucial factor, especially in reactions taking place in different pH environments. In an alkaline medium, negatively charged ions often exhibit higher stability. This is why, when hydrogen peroxide dissociates in such a medium, \(\mathrm{HO}_2^-\) emerges as a stable ion.
Consider these stability factors:

• Anion stability is key; negative ions such as \(\mathrm{HO}_2^-\) are favored as they experience less repulsion in a mainly negative ion surrounding.
• Certain ions stabilize through hydrogen bonding, although concentration of \(\mathrm{OH}^-\) can sometimes complicate interactions.
• The chemical forces in play, including ionic and covalent bonding, influence which ions emerge as most stable during the dissociation process.

Understanding these complexities helps explain why some ions dominate in acidic versus basic environments, guiding reactions for practical applications like synthesis or buffering solutions.