Problem 36 - Chemistry in 30 days

Question

What is formed when iodine is absorbed by hypo solution ? (a) \(\mathrm{Nal}_{3}\) (b) \(\mathrm{Na}_{4} \mathrm{~S}_{4} \mathrm{O}_{6}\) (c) \(\mathrm{Na}_{2} \mathrm{~S}_{4} \mathrm{O}_{6}\) (d) \(\mathrm{Na}_{3} \mathrm{~S}_{4} \mathrm{O}_{6}\)

Step-by-Step Solution

Answer

(c) \(\mathrm{Na}_{2} \mathrm{~S}_{4} \mathrm{O}_{6}\)

Step 1: Understand the Components

First, identify the components: iodine (5I_25) and hypo solution, which is commonly known as sodium thiosulphate (5Na_2S_2O_35).

Key Concepts

Sodium Thiosulphate

Sodium thiosulphate is a versatile inorganic compound with the chemical formula \(\text{Na}_2\text{S}_2\text{O}_3\). Often used in laboratories, it is known for its ability to neutralize iodine, which is why it's sometimes called hypo. This compound is highly soluble in water, making it a practical choice for many reactions.

• Common uses: Photography for fixing solutions
• Application: Reducing agent in chemical reactions
• Form: Typically appears as a white or colorless crystalline substance

Sodium thiosulphate plays a crucial role in reactions where iodine needs to be removed or neutralized. Its effective interaction with iodine makes it a valuable reagent in chemical processes.

Iodine

Iodine, symbolized as \(\text{I}_2\), is a dark-colored solid at room temperature. It is a diatomic molecule, meaning it consists of two iodine atoms covalently bonded. Iodine is essential for various industrial and medical applications.

• Halogen: Part of the halogen group in the periodic table
• Uses: Antiseptic, nutritional supplement, in radiography
• Reaction Behavior: Reacts readily with other elements and compounds

In reactions such as the one with sodium thiosulphate, iodine is often reduced or transformed, resulting in less reactive products. Understanding iodine's characteristics helps in predicting its behavior in chemical reactions.

Chemical Reaction Products

When sodium thiosulphate reacts with iodine, the iodine is reduced, and a new product is formed. The reaction culminates in the formation of sodium tetrathionate \(\text{Na}_2\text{S}_4\text{O}_6\). This product is less reactive compared to the reactants and marks the completion of the reaction.

• Reduction Process: Iodine's oxidation state changes, turning into iodide
• New Product: Formation of sodium tetrathionate is the key to understanding the reaction's outcome

These products are essential for various applications and understanding the outcome of chemical reactions.

Inorganic Chemistry

Inorganic chemistry is the study of inorganic compounds, typically those that do not contain carbon-hydrogen bonds. Reactions involving sodium thiosulphate and iodine fall under this category. These reactions display fundamental concepts in how different elements interact.

• Key Focus: Study of minerals, metals, and different inorganic substances
• Application: Used to synthesize new materials, understand metal behaviors, and more
• Relevance: Central in industries ranging from pharmaceuticals to manufacturing

The understanding of inorganic reactions, like the one involving iodine and sodium thiosulphate, is crucial for solving complex problems in chemistry and helps in designing efficient industrial processes.

Chemical Equations

Chemical equations are symbolic representations of chemical reactions. For the specific reaction between iodine and sodium thiosulphate, the equation helps describe the process and the products formed.
Example equation:\[\text{I}_2 + 2 \text{Na}_2\text{S}_2\text{O}_3 \rightarrow 2\text{NaI} + \text{Na}_2\text{S}_4\text{O}_6\] This equation breaks down the transformation of iodine and sodium thiosulphate into different compounds, showcasing stoichiometry—the calculation of reactants and products in chemical reactions.

• Symbols: Represent elements and compounds
• Coefficients: Indicate the proportion of molecules involved
• Arrow: Shows the direction of the reaction

Understanding chemical equations allows chemists to predict how substances will react together and what they will form, thereby helping to control and utilize reactions in practical applications.