Problem 64 - A Complete Resource Book in Chemistry for JEE Main

Question

Hydrolysis of \(\mathrm{NCl}_{3}\) gives \(\mathrm{NH}_{3}\) and \(\mathrm{X}\). Which of the following is \(\mathrm{X} ?\) (a) \(\mathrm{HClO}_{4}\) (b) \(\mathrm{HClO}_{3}\) (c) \(\mathrm{HOCl}\) (d) \(\mathrm{HClO}_{2}\)

Step-by-Step Solution

Answer

The product \(\mathrm{X}\) is \(\mathrm{HOCl}\), option (c).

Step 1: Write the Hydrolysis Reaction

First, write the balanced chemical equation for the hydrolysis of nitrogen trichloride (\(\mathrm{NCl}_3\)). The hydrolysis of \(\mathrm{NCl}_3\) involves its reaction with water to form ammonia (\(\mathrm{NH}_3\)) and another product \(\mathrm{X}\). The chemical equation is: \[\mathrm{NCl}_3 + 3\mathrm{H}_2\mathrm{O} \rightarrow \mathrm{NH}_3 + 3\mathrm{HOCl}\] In this equation, it's clear that \(\mathrm{X} = \mathrm{HOCl}\).

Step 2: Determine the Product X

Based on the hydrolysis reaction written in Step 1, compare the options given in the problem with the products of the reaction. The product \(\mathrm{X}\) matches the compound \(\mathrm{HOCl}\) which is hypochlorous acid. Thus, the answer can be identified as option (c).

Key Concepts

Hydrolysis Reaction

A hydrolysis reaction involves breaking down a compound by reacting it with water. This type of reaction is crucial in many chemical processes and in the breakdown of different compounds. In the context of our exercise, we see hydrolysis applied to nitrogen trichloride, a molecule that reacts with water to form new products.
This reaction typically occurs when the water causes a cleaving of bonds within the compound, leading to the formation of new, generally simpler compounds. The main reactants in a hydrolysis reaction include:

• A compound (like nitrogen trichloride in our case)
• Water, which facilitates the breakdown

Through hydrolysis, hydrogen atoms (H) from water often attach to one section of the compound, while hydroxide groups (OH) do the same with another section. This results in the formation of discrete compounds, such as ammonia and hypochlorous acid in our particular instance of hydrolysis.

Nitrogen Trichloride

Nitrogen trichloride ( ext{NCl}_3 ) is a yellow, oily chemical compound known for being highly reactive and explosive. It is formed by treating ammonium salts with chlorine gas. Due to its reactivity, it easily engages in hydrolysis reactions.
When nitrogen trichloride undergoes hydrolysis, it splits, forming ammonia ( ext{NH}_3 ) and hypochlorous acid ( ext{HOCl} ) as the notable products. Key properties of nitrogen trichloride include:

• Unstable, particularly when subjected to shock or applied pressure
• Has a strong chlorine smell
• Dissolves in organic solvents easily

This compound presents hazards due to its explosiveness, requiring careful handling, especially when dealing with it in a laboratory or industrial setting.

Hypochlorous Acid

Hypochlorous acid ( ext{HOCl} ) is an important chemical compound, known for its strong disinfectant properties. It's the active compound in many household bleaches and disinfectants used to sanitize surfaces.
In the exercise, hypochlorous acid emerges as the product of the hydrolysis of nitrogen trichloride. This formation can be understood by its tendency to form when chlorine-containing compounds react with water. Some features of hypochlorous acid include:

• Effective at killing bacteria, viruses, and fungi
• Formed in a weak acid solution, showcasing acidity property
• Used extensively in water treatment facilities and sanitation

Hypochlorous acid is considered safe in diluted forms and is often used for disinfecting drinking water and in healthcare settings to ensure microbial safety.