Problem 27 - 43 Years JEE ADVANCED (1978-2020) + JEE MAIN Chapterwise & Topicwise Solved Papers Chemistry

Question

Iodine reacts with hot \(\mathrm{NaOH}\) solution. The products are NaI and .......

Step-by-Step Solution

Answer

The missing product is sodium iodate ( \(NaIO_3\) ).

Step 1: Identify the reactants

The reactants given in the problem are iodine (\(I_2\)) and sodium hydroxide (\(NaOH\)).

Step 2: Recall the typical reaction

In a reaction between iodine and sodium hydroxide, iodine (\(I_2\)) reacts with hot concentrated \(NaOH\)) to form sodium iodide (\(NaI\)), sodium iodate (\(NaIO_3\)), and water (\(H_2O\)).

Step 3: Write the balanced chemical equation

The balanced equation for the reaction is: \[ 3I_2 + 6NaOH \rightarrow 5NaI + NaIO_3 + 3H_2O \]

Step 4: Identify all the products

From the balanced equation, the products of the reaction are sodium iodide (\(NaI\)), sodium iodate (\(NaIO_3\)), and water (\(H_2O\)).

Key Concepts

Sodium Iodide

Sodium Iodide, denoted as \( \text{NaI} \), is a compound that forms when iodine reacts with sodium hydroxide. This compound is made up of sodium (\( \text{Na} \)) and iodide ions (\( \text{I}^- \)).
It is an inorganic salt commonly used in various applications, including medical imaging solutions and nutritional supplements in the iodine form.Here are some key points about Sodium Iodide:

• It appears as a white crystalline solid.
• It is highly soluble in water, making it easy to mix into solutions.
• This compound plays a significant role in the reaction by being one of the primary products.

By understanding \( \text{NaI} \)'s role in the reaction, we connect the reactants to one of their final states. This helps students appreciate the transformation that occurs in these chemical processes.

Sodium Iodate

Sodium Iodate, \( \text{NaIO}_3 \), is another product formed in the reaction between iodine and sodium hydroxide. Unlike sodium iodide, sodium iodate contains an iodate ion (\( \text{IO}_3^- \)), which alters its chemical properties.

Sodium Iodate is typically used as an oxidizing agent.Significant insights about Sodium Iodate include:

• It appears as a crystalline powder, usually white.
• It is less soluble in water compared to sodium iodide.
• Plays a crucial role in the chemical reaction by using iodine in a different oxidation state.

Understanding the presence of \( \text{NaIO}_3 \) in the reaction highlights the diversity of products possible from a single set of reactants. It also illustrates the complexity of chemical reactions beyond simple combinations.

Balanced Chemical Equation

Writing a balanced chemical equation is essential to understanding chemical reactions, as it provides a precise account of all reactants and products. In this reaction, the equation is:\[ 3I_2 + 6NaOH \rightarrow 5NaI + NaIO_3 + 3H_2O \]

Balancing chemical equations ensures that each type of atom has the same number on both sides of the reaction, adhering to the law of conservation of mass.
The balanced equation for iodine and sodium hydroxide reaction clarifies the following:

• Three molecules of iodine react with six molecules of sodium hydroxide.
• The reaction produces five molecules of sodium iodide, one molecule of sodium iodate, and three molecules of water.
• This formalizes the stoichiometry, making sure the equation follows chemical laws.

A balanced equation not only assures the correctness of the reaction but also aids in calculating the reactant needed and the product formed. This foundational skill in chemistry helps students understand more complex reactions.