Question

In how many of the following compounds of sulphur, there is S-S bond (only single bond not double bond between two sulphur atoms). \(\mathrm{H}_{2} \mathrm{~S}_{2} \mathrm{O}_{4}, \mathrm{H}_{2} \mathrm{~S}_{2} \mathrm{O}_{3}, \mathrm{H}_{2} \mathrm{~S}_{2} \mathrm{O}_{5}, \mathrm{H}_{2} \mathrm{~S}_{2} \mathrm{O}_{6}, \mathrm{H}_{2} \mathrm{~S}_{2} \mathrm{O}_{7}\), \(\mathrm{H}_{2} \mathrm{~S}_{2} \mathrm{O}_{8}, \mathrm{~S}_{2} \mathrm{Cl}_{2}\), cyclic \(\left(\mathrm{SO}_{3}\right)_{3}\) (1) 7 (2) 6 (3) 5 (4) 4

Short answer

6 of the compounds contain an S-S single bond.

Step-by-step solution

- Identify the structures

Identify the molecular structures of each compound given in the problem: 1. \(\text{H}_2\text{S}_2\text{O}_4\)2. \(\text{H}_2\text{S}_2\text{O}_3\)3. \(\text{H}_2\text{S}_2\text{O}_5\)4. \(\text{H}_2\text{S}_2\text{O}_6\)5. \(\text{H}_2\text{S}_2\text{O}_7\)6. \(\text{H}_2\text{S}_2\text{O}_8\)7. \(\text{S}_2\text{Cl}_2\)8. Cyclic \((\text{SO}_3)_3\)

- Draw each structure

Draw the Lewis structures for each compound to clearly see the bonds present. For example, draw the structure for \(\text{H}_2\text{S}_2\text{O}_4\) and look for the presence of an S-S bond.

- Check for S-S bonds

Inspect each structure to determine if there is a single S-S bond (not a double bond). Mark or identify the compounds that have this single S-S bond.

- Count the compounds with S-S bonds

Count how many compounds contain a single S-S bond. Review each structure to make sure the count is correct.

- Identify the answer

Compare the count from the previous step with the provided options and select the correct answer.

Key concepts

Chemical Bonding

Chemical bonding refers to the force that holds atoms together in a compound. These bonds can be ionic, covalent, and metallic. In the context of sulphur compounds, we often deal with covalent bonds, where atoms share electrons to achieve stability.
Stable sulphur compounds form due to sharing of electrons between sulphur atoms and other elements, such as oxygen or hydrogen. The type of bond formed can affect the chemical properties and reactivity of the compound.
There are a few primary types of covalent bonds to be aware of:

• Single Bonds: where one pair of electrons is shared between two atoms.
• Double Bonds: where two pairs of electrons are shared.
• Triple Bonds: where three pairs of electrons are shared, though these are much less common for sulphur compounds.

Lewis Structures

Lewis structures are diagrams that represent the bonding between atoms in a molecule as well as any lone pairs of electrons that may exist. They are crucial for visualizing the arrangement of atoms and help understand the molecular geometry.
To draw a Lewis structure, follow these steps:

• Determine the total number of valence electrons in the molecule.
• Write the symbols for the atoms and connect them with single bonds.
• Distribute the remaining electrons to satisfy the octet rule for each atom (each atom should have 8 electrons in its valence shell, except for hydrogen, which needs 2).
• Convert lone pairs into double or triple bonds if necessary to complete the octets.

For example, in the compound \(\text{H}_2\text{S}_2\text{O}_4\), you would start by adding up the valence electrons of hydrogen, sulphur, and oxygen, then arrange them to visualize the molecule's structure. This allows you to see if there are any single S-S bonds present.

Sulphur-Sulphur Single Bonds

Sulphur-sulphur single bonds refer to a covalent bond formed between two sulphur atoms, where only one pair of electrons is shared. These single bonds are crucial in determining the properties of various sulfur compounds.
The presence of a sulphur-sulphur single bond can influence:

• Stability: Single bonds are usually stable and less reactive compared to double bonds.
• Configuration: Only allowing single bonds changes the molecular shape and bond angles.
• Reactiveness: Compounds with S-S single bonds might react differently when subjected to chemical reactions as compared to those with double bonds.

In the original exercise, you were asked to identify sulphur compounds that contain these single bonds. By drawing the Lewis structures, you can check for the presence of these bonds and determine how many compounds in the given list have an S-S single bond.
Understanding the concept of S-S single bonds is essential for predicting the behavior and interaction of sulphur-containing compounds in different chemical environments.