Question

For the preparation of sodium thiosulphate by "Springs reaction" the reactants used are: (a) \(\mathrm{Na}_{2} \mathrm{~S}+\mathrm{SO}_{2}\) (b) \(\mathrm{Na}_{2} \mathrm{SO}_{3}+\mathrm{S}\) (c) \(\mathrm{Na}_{2} \mathrm{~S}+\mathrm{Na}_{2} \mathrm{SO}_{3}+\mathrm{I}_{2}\) (d) \(\mathrm{Na}_{2} \mathrm{~S}+\mathrm{Na}_{2} \mathrm{SO}_{3}+\mathrm{Cl}_{2}\)

Short answer

Option (b): \( \mathrm{Na}_{2} \mathrm{SO}_{3} + \mathrm{S}\) is used in the Springs reaction.

Step-by-step solution

Understanding the Reaction

'Springs reaction' refers to the synthesis of sodium thiosulphate through a specific chemical reaction. We need to identify which set of reactants among the given options result in the formation of sodium thiosulphate.

Review Option A

Option (a) contains the reactants \(\mathrm{Na}_{2} \mathrm{~S}+\mathrm{SO}_{2}\). These can react to form sodium thiosulphate through further steps, but typically not directly used in the Springs reaction.

Examine Option B

Option (b) lists \(\mathrm{Na}_{2} \mathrm{SO}_{3}+\mathrm{S}\), which indeed represents part of the classic synthesis method for sodium thiosulphate, as they react to form \(\mathrm{Na}_{2} \mathrm{S}_{2}\mathrm{O}_{3}\).

Assess Option C

Option (c) includes \(\mathrm{Na}_{2} \mathrm{~S} + \mathrm{Na}_{2} \mathrm{SO}_{3} + \mathrm{I}_{2}\). This does not typically lead to formation of sodium thiosulphate under standard conditions associated with 'Springs reaction.'

Evaluate Option D

Option (d) has the reactants \(\mathrm{Na}_{2} \mathrm{~S} + \mathrm{Na}_{2} \mathrm{SO}_{3} + \mathrm{Cl}_{2}\). This set of reactants doesn't typically produce sodium thiosulphate by the Springs reaction process.

Conclusion

The correct set of reactants for the 'Springs reaction' to produce sodium thiosulphate is identified in option (b): \(\mathrm{Na}_{2} \mathrm{SO}_{3} + \mathrm{S}\).

Key concepts

Springs Reaction

The Springs Reaction is a specific process used primarily in inorganic chemistry to synthesize sodium thiosulphate. This reaction is named after the springs of geothermal areas where unique chemical processes occur.
In the Springs Reaction, the most common reactants involved are sodium sulfite (\(\mathrm{Na}_{2} \mathrm{SO}_{3}\)) and sulfur (\(\mathrm{S}\)). These react to form sodium thiosulphate (\(\mathrm{Na}_{2} \mathrm{S}_{2}\mathrm{O}_{3}\)), a compound with various practical applications, including as a fixing agent in photography and in chemical dechlorination processes.

• The reactants: Sodium sulfite and sulfur.
• The product: Sodium thiosulphate (\(\mathrm{Na}_{2} \mathrm{S}_{2}\mathrm{O}_{3}\)).
• Applications: Used in fixing photographic negatives and prints.

Understanding the Springs Reaction is particularly important for students of inorganic chemistry, as it highlights the specific conditions and reactants needed to produce useful compounds. This reaction is a fundamental example of how simple reactants combine to create a product with significant utility.

Chemical Reactions

Chemical reactions are processes where substances, called reactants, transform into different substances, called products. This transformation involves the breaking and forming of chemical bonds, a process that is essential to understand the synthesis of compounds like sodium thiosulphate.
In the context of the Springs Reaction:

• Reactants: When sodium sulfite and sulfur react, a new compound, sodium thiosulphate, is formed.
• Bond formation: The reaction involves breaking old bonds and forming new ones, which often requires specific conditions.
• Indicators: Successful reactions depend on factors such as temperature, concentration, and pressure.

The chemistry behind reactions like these helps to illustrate broader themes in inorganic chemistry, such as the reactivity of certain substances and how elemental properties influence the formation of compounds. Understanding chemical reactions requires recognizing these dynamic processes and how they create the diverse materials used in various industries.

Inorganic Chemistry

Inorganic Chemistry is a branch of chemistry focused on compounds that do not primarily contain carbon. It covers a vast array of elements and compounds, highlighting how they combine to form products like sodium thiosulphate.
This field is crucial for understanding reactions like the Springs Reaction, as it:

• Studying Elements: Emphasizes the properties of metals, salts, minerals, and gases.
• Reactions: Explores how different elements and compounds interact, leading to new material formation.
• Applications: Relates to various fields such as materials science, pharmacology, and industrial processes.
• Structure and Bonding: Considers how atomic structures and electron configurations affect chemical behavior.

Inorganic chemistry is essential for students to grasp the underlying principles that guide the synthesis and application of inorganic compounds like sodium thiosulphate. The foundational knowledge from this branch of science informs practical applications in numerous real-world scenarios, from industrial processes to environmental technology.