Problem 78 - A Complete Resource Book in Chemistry for JEE Main

Question

The acid having O-O bond is (a) \(\mathrm{H}_{2} \mathrm{~S}_{2} \mathrm{O}_{3}\) (b) \(\mathrm{H}_{2} \mathrm{~S}_{2} \mathrm{O}_{6}\) (c) \(\mathrm{H}_{2} \mathrm{~S}_{2} \mathrm{O}_{\mathrm{s}}\) (d) \(\mathrm{H}_{2} \mathrm{~S}_{4} \mathrm{O}_{6}\)

Step-by-Step Solution

Answer

The acid with an O-O bond is (c) \( \mathrm{H}_{2} \mathrm{~S}_{2} \mathrm{O}_{8} \).

Step 1: Understand the Problem

We need to find out which of the given acids has an O-O bond. The structure of each compound should be analyzed to determine the presence of the O-O bond.

Step 2: Analyze Each Compound

Let's look at each acid one by one and their potential structures:(a) \( \mathrm{H}_{2} \mathrm{~S}_{2} \mathrm{O}_{3} \): This is thiosulfuric acid. Typically, it contains a sulfur-sulfur bond, not an oxygen-oxygen bond.(b) \( \mathrm{H}_{2} \mathrm{~S}_{2} \mathrm{O}_{6} \): Usually defined as dithionic acid. The structure of these acids involves \( -S-O-O-S- \) bonds, indicating the presence of an O-O bond.(c) \( \mathrm{H}_{2} \mathrm{~S}_{2} \mathrm{O}_{8} \): Known as peroxodisulfuric acid, it contains a peroxide linkage which is an O-O bond.(d) \( \mathrm{H}_{2} \mathrm{~S}_{4} \mathrm{O}_{6} \): This is tetrathionic acid, characterized by sulfur-sulfur bonds along with typical sulphate linkages, not an O-O bond.

Step 3: Determine the Acid with the O-O Bond

From the analysis:- (b) \( \mathrm{H}_{2} \mathrm{~S}_{2} \mathrm{O}_{6} \) has an O-O bond as part of the dithionic acid structure.- (c) \( \mathrm{H}_{2} \mathrm{~S}_{2} \mathrm{O}_{8} \) also has an O-O bond due to the peroxide linkage in peroxodisulfuric acid.However, the primary example of an O-O bond mentioned in common acid names is the peroxide bond in peroxodisulfuric acid.

Key Concepts

Peroxide Linkage

A peroxide linkage is a unique type of chemical bond between two oxygen atoms. This bond is characterized by the formula

• −O−O−

Such bonds are known for their unique property of containing more charge density compared to a standard oxygen bond. In chemistry, peroxide linkages are predominantly found in compounds like hydrogen peroxide, and importantly, in acids such as peroxodisulfuric acid.
Peroxides are typically strong oxidizers. The

• strength of the O-O bond,
• its tendency to break forming radicals,
• and usage in various chemical processes makes them notable in both academic and industrial fields.

Dithionic Acid

Dithionic acid, chemically represented as

• H_{2}S_{2}O_{6}

has a structure featuring a distinctive segment:

• −S−O−O−S− linkage.

This series of atoms includes the important O-O bond, marking it as a sulfur compound with a peroxide linkage. 
Considered to be an unusual sulfur compound, it exhibits an interesting mechanism by forming stable sulfur-oxygen chains. This characteristic influences a participating O-O bond, thus making it reactive.
Understanding the structure and properties of dithionic acid deepens the grasp of peroxide linkages and their importance in sulfur-containing compounds.

Peroxodisulfuric Acid

Peroxodisulfuric acid is a compelling chemical compound noted for its

• potent oxidizing behaviors

and is typically expressed as

• H_{2}S_{2}O_{8}.

The presence of the peroxide linkage,

• −O−O−,

is what categorizes this compound. 
The structure accounts for the strong O-O bond adjacent to sulfur atoms, enhancing both its stability and reactivity. This molecular configuration allows peroxodisulfuric acid to participate significantly in redox reactions.
It is predominantly used in

• chemical synthesis,
• industrial processes like cleaning and bleaching,
• and various applications requiring strong oxidizing agents.

Peroxodisulfuric acid is a remarkable example of a compound that illustrates the power and utility of peroxide linkages.