Question

Boron nitride on reacting with caustic alkali gives (a) \(\mathrm{NO}_{2}\) (b) \(\mathrm{N}_{2} \mathrm{O}\) (c) \(\mathrm{Na}_{2} \mathrm{BO}_{2}\) (d) \(\mathrm{NH}_{3}\)

Short answer

The main product is (c) \(\mathrm{Na}_{2}\mathrm{BO}_{2}\).

Step-by-step solution

Identify the Reactants and Reaction Type

Boron nitride (BN) is reacting with a caustic alkali, typically sodium hydroxide (NaOH). This is a type of chemical reaction that involves an acid-base interaction.

Write the Reaction Equation

The reaction between boron nitride and caustic alkali can be represented by the equation: \( BN + NaOH \rightarrow Na_{2}BO_{2} + NH_{3} \). This shows that boron nitride reacts with sodium hydroxide to produce sodium metaborate and ammonia.

Identify the Reaction Products

From the balanced chemical equation, the products formed are sodium metaborate (Na₂BO₂) and ammonia (NH₃).

Choose the Correct Answer

From the list of options, the products Na₂BO₂ and NH₃ are present. Since both are formed, they can match options (c) \(Na_{2}BO_{2} \) and (d) \(NH_{3} \). However, the question may refer to the main recognizable salt formed, which is sodium metaborate \((c)\).

Key concepts

Boron Nitride

Boron nitride (BN) is a fascinating chemical compound that shares many of its physical properties with carbon-based substances like graphite and diamond. It exists in multiple forms or allotropes, the most common being hexagonal boron nitride (h-BN) and cubic boron nitride (c-BN). Hexagonal boron nitride is often compared to graphite due to its similar layered structure and lubricating properties. In contrast, cubic boron nitride is structurally more akin to diamond and is known for its incredible hardness.

When discussing chemical reactions, boron nitride acts differently compared to many other compounds. As seen in the exercise, it can react with caustic alkali, which leads to the formation of various products. This reaction provides insight into boron nitride's basicity and its ability to form salts like sodium metaborate when interacting with strong bases like sodium hydroxide (NaOH).

Understanding the properties of boron nitride, from its hardness and lubrication capabilities to its reactivity, helps in appreciating its wide applications. These applications range from industrial lubricants and high-strength abrasives to thermal and electrical insulators in electronics.

Caustic Alkali

Caustic alkalis include highly basic compounds that have important uses in various chemical processes. The term generally refers to strong bases, among which sodium hydroxide (NaOH, also known as lye) is a prominent example. These substances are characterized by their ability to dissociate in water to form hydroxide ions (OH⁻), making them highly corrosive and efficient at neutralizing acids.

When a caustic alkali like sodium hydroxide encounters substances such as boron nitride, it facilitates the breakdown of the chemical structure, resulting in the production of different compounds. In our reaction scenario, sodium hydroxide reacts with boron nitride to produce sodium metaborate (Na₂BO₂) and ammonia (NH₃).

Due to their high reactivity, caustic alkalis are widely used in manufacturing processes, including the production of paper, textiles, and soaps. Additionally, because of their ability to break down organic matter and neutralize acids, they find usage in cleaning and sanitation applications.

Sodium Metaborate

Sodium metaborate is a chemical compound represented by the formula Na₂BO₂. It is one of the products you obtain when boron nitride reacts with a caustic alkali such as sodium hydroxide. This compound is interesting not only because of its role in chemical synthesis but also due to its diverse applications.

In this particular chemical reaction, sodium metaborate forms through the interaction of the hydroxide ions from the caustic alkali with boron nitride, showcasing how acid-base reactions can lead to the formation of new salts. Sodium metaborate is crucial in many industrial applications. It is used in the production of glass and ceramics, where it assists in lowering the melting point of silica, improving chemical durability, and enhancing clarity.

Besides industrial uses, sodium metaborate also finds roles in agriculture (as a micronutrient supplier) and as a fire retardant in various materials. Its formation through this reaction is a prime example of the utility of chemical transformations in creating valuable compounds for practical applications.