Problem 183 - A Complete Resource Book in Chemistry for JEE Main

Question

Match the following \begin{tabular}{ll} \hline Column-I & Column-II \\ \hline \begin{tabular}{ll} (a) \(\mathrm{H}_{2} \mathrm{SO}_{5}\) & (p) \(\mathrm{S}-\mathrm{S}\) linkage \\ (b) \(\mathrm{H}_{2} \mathrm{~S}_{2} \mathrm{O}_{8}\) & (q) \(+6\) oxidation state \\\ (c) \(\mathrm{H}_{2} \mathrm{~S}_{2} \mathrm{O}_{6}\) & (r) Peroxy linkage \\ (d) \(\mathrm{H}_{2} \mathrm{~S}_{2} \mathrm{O}_{3}\) & (s) \(-2\) oxidation state \\\ \hline \end{tabular} \end{tabular}

Step-by-Step Solution

Answer

(a)-(r), (b)-(q), (c)-(p), (d)-(s)

Step 1: Analyzing compound H2SO5

The compound \( \mathrm{H}_{2} \mathrm{SO}_{5} \) is known as Caro's acid. It contains a peroxide linkage, which can be denoted by an O-O bond that is characteristic of peroxy compounds. Thus, \( \mathrm{H}_{2} \mathrm{SO}_{5} \) matches with (r) Peroxy linkage.

Step 2: Analyzing compound H2S2O8

The compound \( \mathrm{H}_{2} \mathrm{~S}_{2} \mathrm{O}_{8} \) is known as Peroxodisulfuric acid. It has a structure with a peroxy (O-O) linkage and a \( +6 \) oxidation state for sulfur. Since it matches both peroxy linkage and +6 oxidation, we choose the best match based on typical problems: (q) +6 oxidation state.

Step 3: Analyzing compound H2S2O6

The compound \( \mathrm{H}_{2} \mathrm{~S}_{2} \mathrm{O}_{6} \), known as Dithionic acid, contains an S-S linkage between two sulfur atoms. Therefore, it corresponds to (p) \( \mathrm{S}-\mathrm{S} \) linkage.

Step 4: Analyzing compound H2S2O3

The compound \( \mathrm{H}_{2} \mathrm{~S}_{2} \mathrm{O}_{3} \), known as Thiosulfuric acid, involves sulfur in a reduced state of \( -2 \) oxidation for one of the sulfur atoms in the molecule due to the additional sulfur atom replacing an oxygen atom from sulfuric acid. Hence, it matches with (s) \(-2\) oxidation state.

Key Concepts

Oxidation States

Oxidation states, also known as oxidation numbers, represent the degree of oxidation of an atom in a chemical compound. Simplifying matters, it can be thought of as the "charge" an atom would have if all chemical bonds were completely ionic. Understanding oxidation states is key as they allow chemists to keep track of electron transfer in chemical reactions.

Several rules simplify the process of determining oxidation states in a compound.

• The oxidation state of an atom in its elemental form is always zero.
• For a monatomic ion, the oxidation state is equal to the ion charge.
• Oxygen usually has an oxidation state of -2 in compounds, except in peroxides where it is -1.
• Hydrogen typically has an oxidation state of +1 when bonded to non-metals and -1 when bonded to metals.

When analyzing the oxidation states in the provided compounds:
In \(\mathrm{H}_{2} \mathrm{SO}_{5}\), knowing oxygen's typical oxidation state is -2 (or -1 in a peroxy linkage), and hydrogen is +1, we find sulfur balances this by having an oxidation state of +6.
Similarly, in \(\mathrm{H}_{2} \mathrm{~S}_{2} \mathrm{O}_{8}\), again, sulfur assumes an oxidation state of +6 within the complex structure of peroxodisulfuric acid.

Peroxy Compounds

Peroxy compounds are chemical species containing a peroxide linkage, denoted as an O-O bond. This bond is distinctive due to its weak nature and high reactivity, playing a significant role in many chemical reactions. Peroxy compounds are widespread in organic chemistry, with their reactions being crucial in various synthesis pathways.

In inorganic chemistry, peroxy linkings indicate the presence of a particular type of bond layout which affects the properties and reactivity of the compound.

• The O-O bond in peroxides is less stable and often readily cleaves, making these compounds effective as bleaching agents and initiators in polymerization reactions.
• Compounds like hydrogen peroxide (\(\mathrm{H}_2\mathrm{O}_2\)) and peroxodisulfuric acid (\(\mathrm{H}_2\mathrm{~S}_2 \mathrm{O}_8\)) are common examples that exhibit these linkages.

In the exercise, \(\mathrm{H}_{2} \mathrm{SO}_{5}\) also demonstrates this linkage showing its classification as a peroxy compound. This linkage contributes to the compound’s characteristics and reactivity, particularly in oxidizing processes.

Linkages in Sulfur Compounds

Inorganic compounds often employ various linkages that impact their chemistry significantly. Sulfur compounds are especially noteworthy for their diversity, including the formation of S-S linkages.

S-S linkages, also known as disulfide bridges, are bonds between two sulfur atoms.

• These linkages are pivotal in biochemistry, helping maintain protein structures through covalent bonding. In chemistry, these are seen in compounds such as dithionic acid (\(\mathrm{H}_{2} \mathrm{~S}_{2} \mathrm{O}_{6}\)), where an S-S bond is present.
• The S-S bond's stability offers unique characteristics to the compound, influencing its reactivity and functionality in chemical reactions.

Another important linkage involves differing oxidation states—such as the reduced state seen in thiosulfuric acid (\(\mathrm{H}_{2} \mathrm{~S}_{2} \mathrm{O}_{3}\)) where a sulfur atom replaces an oxygen atom. Consequently, this results in unique properties compared to its sulfuric acid parent, where sulfur assumes a distinct oxidation state of -2 in this linkage, showcasing the remarkable versatility and complexity of sulfur compounds.